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SANDIA REPORTSAND84-0468 * UC-70Unlimited ReleasePrinted March 1989
Yucca Mountain Project
Experimental Plan for Investigating WaterMovement Through Fractures
E. A. Klavetter, R. R. Peters, B. M. Schwartz
Prepared bySandia National LaboratoriesAlbuquerque, New Mexico 87185 and Uvermore, California 94550for the United States Department of Energy
under Contract DE-AC04-760P_0789
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"Prepared by Yucca Mountain Project (YMP) participants as part of theCivilian Radioactive Waste Management Program (CRWM). The YMP ismanaged by the Yucca Mountain Project Office of the U.S. Department ofEnergy, Nevada Operations Office (DOE/NV). YMP work is sponsored by theOffice of Geologic Repositories (OGR) of the DOE Office of Civilian Radio-active Waste Management (OCRWM)."
Issued by Sandia National Laboratories, operated for the United StatesDepartment of Energy by Sandia Corporation.NOTICE: This report was prepared as an account of work sponsored by anagency of the United States Government. Neither the United States Govern-ment nor any agency thereof, nor any of their employees, nor any of theircontractors, subcontractors, or their employees, makes any warranty, expressor implied, or assumes any legal liability or responsibility for the accuracy,completeness, or usefulness of any information, apparatus, product or processdisclosed, or represents that its use would not infringe privately owned rights.Reference herein to any specific commercial product, process, or service bytrade name, trademark, manufacturer, or otherwise, does not necessarilyconstitute or imply its endorsement, recommendation, or favoring by theUnited States Government, any agency thereof or any of their contractors orsubcontractors. The views and opinions expressed herein do not necessarilystate or reflect those of the United States Government, any agency thereof orany of their contractors.
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NTIS price codesPrinted copy: A06Microfiche copy A01
DistributionCategory UC-70
SAND84-0468Unlimited Release
Printed March 1989
EXPERIMENTAL PLAN FOR INVESTIGATINGWATER MOVEMENT THROUGH FRACTURES
E. A. Klavetter, R. R. Peters and B. M. SchwartzNevada Nuclear Waste Storage Investigations Project Department
Sandia National LaboratoriesAlbuquerque, New Mexico 87185
ABSTRACT
The Yucca Mountain site In southern Nevada is being Investigated by the NevadaNuclear Waste Storage Investigations (NNWSI) project*as a possible site for a nuclearwaste repository. The manner in which the water flows downward from the repositorythrough the unsaturated zone to the water table can affect the transport ofradionuclides. The travel time of water across a rock unit is considerably shorter if theflow s predominantly through fractures than if It is predominantly through the rockmatrix. Current data and postulated physical models indicate that there is little or nosignificant flow through fractures in the unsaturated zone at Yucca Mountain. Fracturedata are required to increase confidence in this conclusion and would be used qualitativelyto increase understanding and quantitatively in modeling. The evaluation of water flow infractures Is also necessary for abnormal scenarios where significant fracture flow mayoccur because of future climatic conditions. An experimental system is described for thepurpose of investigating the movement of water through fractures. The system will beused to perform the tests described in this report.
* The name of the NNWSI Project was changed to Yucca Mountain Project (YMP)on November 9, 1988.
I
ACKNOWLEDGEMENTS
The authors wish to express their appreciation to J. R. Wayland and D. 0. Lee of Sandia +
National Laboratories for their help In formulating initial concepts and for their
comments and suggestions concerning the Laboratory Impedance Measurement of
Fracture Flow technique. We would also like to express our appreciation to the peer
reviewers, R. M. Zimmerman and M. J. Martinez of Sandia National Laboratories, for
their comments and suggestions.
ii
TABLE OF CONTENTS
Page
INTRODUCTION.......................................................................1.........................
OBJECTIVES ............. . . . ..E............. ............ 5............................... 5
DESCRIPTION OF LABORATORY IMPEDANCE MEASUREMENTS OFFRACTURE FLOW (LIMI8FF)......6
Description of Technique ........Desritin o T ch iqu ............................................ .......................... Establishment of Relationship between Impedance Response
and Water Volume and Movement .16
TEST DESCRIPTION.. 21
EXPECTED RESULTS . . .27
EXPERIMENTAL APPARATUS CONFIGURATION. 33
General Description... 33System Components . . . 37
Pore-Fluid Loop . . .57Confining-Fluto Loop . . . 38Pressure Vessel ... 38Instrumentation.................................................................................. 39
QUALITY ASSURCANCE .42
Quality Assurance Procedure (QAP) . . .42Safe Operating Procedure (SOP) . . .42Identification and Control of Samples . . .42Control of Measuring and Test Equipment. . . 43Sample Preparation . . . .45Quality Assurance Records .. . .45System Function Verification . . . .45
SAFETY............................................................................................................ 47
SUMMAR Y ......... .............................................................................................. 48
REFERENCES. .................................................................................................. 49
Appendix A Sample Preparation ... A-
Appendix B Procedure for Placement of an ElectrodeGild on Rock Samples .B-1
Appendix C Quality Assurance Procedure .................................................... C-I
Appendix D Safe Operating Procedure ........................................................ D-l
I1
FIGURES
Page
1. Schematic of the Effects on Measured Capacitance When aConductive Fluid is Displaced by an Insulating Fluid in aFracture...................................................................................................... 10
2. Response to be Expected for Idealized Frontal nstabilities .............................. 12
3. Definition of Times Associated with Frontal Instability Measurements ............. 13
4. Computation of the Areal Fraction, W. Occupied by Fingers in anAdvancing Front ................................................................ 15
5. Simulated Fracture ................................................................ 18
6a. Core Sample Encased In Core Holder Assembly with CutawayView of the Fracture Surface ................................................................ 23
6b. Electrode Grid Pattern on the Fracture Surface .............................................. 23
7. Fracture Aperture Versus the Effective Confining Pressure ............................. 28
8. Normalized Fracture Permeability Versus the EffectiveConfining Pressure ................................................................ 29
9. Normalized Fracture Permeability Versus the EffectiveConfining Pressure ................................................................ 30
10. Fracture Flow Experimental Apparatus Schematic .34
11. Instrumentation/Data Acquisition System ....................................................... 40
TABLES
1. Sample Specification.................................................................................... 22
2. Equipment and Instrumentation Specification .35
3. Calibration Guidelines .44
iv
INTRODUCTION
The Nevada Nuclear Waste Storage Investigations (NNWSI) project is characterizing
the unsaturated geologic formations at Yucca Mountain, on and adjacent to the Nevada
Test Site, as a possible site for a high-level nuclear waste repository. Flow through
fractures is considered in the NNWSI project to be a potential mechanism for major water
movement in certain units of Yucca Mountain. The travel time of water across a rock
unit Is considerably shorter if the flow is predominantly through fractures than if it is
predominantly through the rock matrix. Therefore, the time for radionuclides to travel
from the repository to the accessible environment is affected by the manner in which the
water moves through the rock units. Current data and postulated physical models indicate
that there is little or no significant flow through fractures in the unsaturated geologic
formations at Yucca Mountain. Fracture data are required to increase confidence in this
conclusion and would be used qualitatively to increase understanding and quantitatively in
modeling. The evaluation of water flow In fractures is also necessary for abnormal
scenarios where significant fracture flow may occur because of future climatic conditions.
In order to model the possible transport of radionuclides through the rock mass, it is
necessary to characterize the movement of water, both through the fractures and the
porous matrix. In some geologic units, such as the densely welded and highly fractured
Topopah Spring Member, the fracture conductivity may be many orders of magnitude
larger than the conductivity of the matrix itself, with the bulk saturated conductivity of
the rock mass therefore approaching the value of the fracture-saturated conductivity.
From available data, the matrix conductivity of the Topopah Spring Member is on the
order of 4 x l0 9 cm/s or less, with the matrix conductivity of the non-welded tuffs
generally on the order of I x 106 cm/s or less (1). Although there are few bulk
permeability data for tuff available to date, field measurements in G-Tunnel on the
-I-
Nevada Test Site (2) show fracture permeabilities of 10 - 1000 darcies (I darcy 10 3
cm/s), which are much higher than the rock matrix permeabilities (10 - 10-8
darcies), indicating that fractures have the potential to carry a large fraction of water
flux when flow occurs. Because little information is available about fracture flow in
tuffaceous rocks, or any other type of rock, new investigations are needed to characterize
the behavior of water flow through natural fractures. Of major interest is the
determination of whether Richard's equation (3), which predicts transient,
saturated/unsaturated flow In porous media, is a valid description of fracture flow, and
whether the "cubic law" can be used for estimating the fracture's saturated permeability
from an estimated average fracture aperture. (In the "cubic law" formulation, the fluid
flow rate Is proportional to the cube of the fracture aperture, b, and the fracture
saturated permeability equal to b 2/12.) Of interest also are the changes in the fracture
permeabilitles (and aperture widths) due to changes in temperature and confining
pressure: the degree of water migration, through capillary forces and diffusion, between
the fracture and the matrix: and the possibility of channeling in a fracture as a dominant
water movement phenomenon.
It Is essential that the constitutive equations used to predict the water flux be valid
for the conditions encountered so that the calculated water velocities and thus
radionuclide transport through the rock mass be accurate. A "cubic law" model, in
conjunction with Richard's equation, is in common use for predicting liquid fluxes through
fractures, but it Is necessary to determine whether that formulation is valid for both the
saturated and the unsaturated conditions that might be encountered at a repository site.
Barton et al.(4) have shown that a measured, geometric-fracture aperture (a real
quantity) may be significantly larger than the equivalent smooth-wall, hydraulic aperture
-2-
that is determined from flow measurements and the "cubic law" model. This Indicates that
predictions of water fluxes using the "cubic law" model, with measured, geometric
fracture aperture values for the fractured rock mass under study, could be significantly in
error. Both geometric and equivalent, smooth-wall hydraulic apertures will be
determined in the experimental test series described in Section 4 to investigate the
difference between the two apertures.
Knowledge of the fracture permeability response to increasing temperature is also
necessary for modeling the environment near the nuclear waste canisters. Because
fracture apertures, and thus fracture permeabilities, decrease with increasing stress,
measurements of the response of fracture permeability to confining pressure are needed
to indicate the relative importance of fracture flow as depth, and thus in situ stress, in a
unit increase. Results from testing samples obtained from different units will show the
variation in flow response between different tuffs and aid in the determination of the
modeling approach to be used in describing the water movement in the geologic units
above the water table.
It is not known whether flow can occur in an unsaturated fracture or whether a
saturated, or nearly saturated, condition must be present in the fracture for the fracture
permeability to be significantly greater than the surrounding matrix permeability. For an
unsaturated flow condition, if it can occur, no Information is available about the curves
describing moisture content and conductivity as a function of pressure head. These two
curves are referred to as "the characteristic curves for unsaturated flow," or simply as
the "characteristic curves." Information is required about the nature of flow behavior
through a fracture at fluid velocities less than the saturated fracture conductivity to
-3-
determine the nature of these characteristic curves for the fracture.
If the flow mechanism appears to be Darcian and follows Richard's equation. it may
also be possible to determine experimentally the characteristic curves (e.g. see Ref 5) for
the fracture. These characteristic curves would make it possible to model the flow
characteristics in a macroscopic sense (without accounting for flow irregularities caused
by fracture surface topography) using current code capabilities. Some preliminary
modeling of flow In a discrete fracture has been done by Martinez (6) using the Sandia
National Laboratories (SNL)-developed code SAGUARO (7) to predict fluid penetration
through the fracture and Into the matrix. Characteristic curves for the fracture were not
measured but postulated to resemble the curves measured for sand. The results of these
calculations would be much more useful if measured rather than postulated fracture
characteristic curves were used.
-4-
OBJECTIVES
The objectives for these experiments are both qualitative and quantitative. Because
there is at this time a severe deficiency in the understanding of the physics of fluid
movement in fractures, especially when the fractures are not completely saturated, a
major qualitative goal Is to increase the understanding of the mechanisms involved in the
movement of water through natural fractures and to evaluate the usefulness of the "cubic
law" constitutive formulation currently used to predict the saturated flow rate in a
fracture. Data are desired on samples representative of the rockmass under study. It is
Important to note that each fractured-tuff core sample (obtained from boreholes in and
around Yucca Mountain) to be tested contains a single, natural, open fracture; i.e., the
fracture In each core sample was not man-made or judged to be induced by drilling and
was thus assumed to have been present In the core sample's In situ state. Unlike tests on
prepared samples where the fractures resemble parallel plates and flow must inherently
be closely predicted by the "cubic law" model, the naturally fractured samples have
fracture surfaces that may induce different flow mechanisms (e.g., channeling for
unsaturated flow or transitional flow behavior between Darcian and wholly turbulent
flow). Strong capillary forces present In the matrix may also alter the water movement
through the fracture, depending on the matrix saturation and water flow rate, causing
water to move from the fracture into the matrix. These different flow mechanisms may
require that a different constitutive equation, or modification of the currently used
formulation, be used to successfully model the water movement through fractures. The
methods used to acquire the information concerning the mechanisms of water movement
through a fracture are described later in this document.
-5-
The quantitative objectives will be the determination of the response of fracture
aperture and saturated permeability to changes In the effective confining pressure on the
sample and to changes in temperature. Information about the variation of fracture
aperture and permeability with stress will indicate the variation of in-situ permeability of
the fractures with depth. This variation is necessary for modeling the hydrologic system
in Yucca Mountain. Data on the temperature dependence of fracture permeability are
necessary for modeling the repository environment near the waste canisters.
All experiments described in this document employ the same basic fracture-flow
apparatus, with modifications made to conduct the individual tests. A major task Is the
development of an experimental system that can be used to
- Observe the fundamental behavior of water movement through a discretenatural, open fracture and the water movement from the fracture to the matrix,
- Determine the validity of applying Richard's equation with a "cubic law" modelassumed to predict the saturated permeability of a natural fracture,
- Determine the response of fracture aperture and permeability to changes inapplied confining pressure that simulate in-situ pressures, and
- Determine the response of fracture aperture and permeability to changes intemperature.
To accomplish the objectives for this experimental series, it will be necessary to
measure not only the macroscopic flow parameters through the fractured samples, such as
the overall flow rate and pressure drop, but also to be able to monitor the flow behavior
of the fluid as it moves through the fracture and cross the fracture surface. To monitor
the water movement within the unsaturated fracture, an instrumentation technique for
making laboratory electrical impedance (capacitance and resistance) measurements of
fracture flow will be employed. As a fluid moves across the fracture surface, the
electrical impedance will vary between locations along the surface In direct relation to
-6-
the saturation. The variation of the impedance on the fracture surface will indicate the
passage of fluid and the nature of the flow paths. Therefore, the electrical impedance
technique provides the means to determine the volume of water (and thus the saturation)
within the fracture between any two designated locations and the flow rate of water
between the locations. This Information is needed for determining fracture apertures,
evaluating the "cubic law" model, and determining fracture hydraulic conductivity as a
function of saturation. This impedance technique is described in the following section.
-7-
DESCRIPTION OF LABORATORY IMPEDANCE MEASUREMENTS
OF FRACTURE FLOW (LIMFF)
Description of Technique
There is an electrical impedance associated with any pair of points on a fracture
surface. The value of this impedance will depend on the electrical properties of the fluid
in the fracture, the fluid volume, and the electrical properties of the surrounding media.
As a fluid (e.g., water) moves across the fracture surface, displacing another fluid (e.g.,
air), the electrical impedance between the pair of points, or electrodes, on the fracture
surface will change. These changes in electrical impedance along the fracture surface
will provide information about the characteristics of fluid movement through the
fracture.
The LIMFF technique will aid in the understanding of how fluid moves through an
open fracture. A similar impedance technique has been used previously by Wayland and
Lee (8) to investigate the movement of oil and brine through sand, but monitoring fluid
movement in rock fractures on a laboratory scale has not been attempted using this
technique. The measurement system consists of parallel, open grid lines electroplated
onto the rock surface forming one side of the fracture, where the signature of the
changing capacitance/conductance will identify the fluid front and its instabilities (if any)
as the fluid moves perpendicularly past the emplaced electrode grid. A core sample,
containing the fracture with the emplaced electrode grid, is confined within a pressure
vessel that allows simulation of in situ stresses and movement of fluid through the
fractured core sample. A brief description of the mechanics of the technique and how the
responses are interpreted is given below.
-8-
To derive an idealized description of the type of response to be expected, consider a
fracture filled with a fluid. For a set of electrodes (wires or an electroplated grid), there
will be some capacitance, C, between any two electrodes given by
AC= I (1)A 4rF
where A Is the area of the electrodes (perpendicular to the fracture surface), is the
spacing, and c is the dielectric constant of the conducting fluid. Now a fluid solution or
some solution with electrical properties (e.g., the dielectric constant, C, and electrical
permeability, K) contrasting those of the original fluid Is injected into the fracture and
begins to move toward the electrodes. As shown in Figure 1, a bank or front will form
that will displace some or most of the non-conducting fluid. For the tests In this
experimental series, water Is the conducting fluid.
Assume that this is an Inherently stable displacement, but with small-scale
turbulence that creates "fingers" (small extensions or fringes) that will move In advance
of the general front. Given the asperities and roughness on the fracture surface, this is a
likely assumption. Let us restrict attention to the case where the electrode spacing is
smaller than the length of the fingers. Before the fingers reach the first electrode, the
capacitance is Cinit (A in Figure 1), but begins to decrease (B In Figure ) as the fingers
occupy some fraction, A. of the area. The capacitance will decrease until the fingers
pass through both electrodes (C) where a constant reading will continue until the front Is
at the first electrode (D). Then, as the front moves through the spaces between the
electrodes, the capacitance will again decrease until the front Is completely pushed
-9-
FLOW PAST _ _ _
ELECTRODES ON -{ oxFRACTURE SURFACE _ _ NT A
DIRECI OF TFRONT DIRECTION OF MOTION K2 L
A;
TIME
I LU L FRONT
Uwz4
4U
LU44IU9
A B
TIME
A B
_,N CI tIJ tt 1 - FRONT
TIME
n Aff rl+ I- - - FRONT
+I U I_ i FRONT
LuUZ A
14
d0.TIME
LU
-4U
.
4
I JLJULLFRONT gg4Q
0 C D~E
TIME
A B
TIME
Figure 1. Schematic of the Effects on Measured Capacitance When aConductive Fluid is Displaced by an Insulating Fluid in aFracture
-10-
through the second grid (E), after which the capacitance remains constant (F). The
response curve will, of course, change with electrical properties of the fluids. These
properties can be measured easily for the fluids of interest for all expected conditions
(e.g., temperature, pressure, fluid pH).
The magnitude and shape of the response curve will depend on the resistivity and
dielectric constants of the fluids. If the ratio of the resistivity of the displaced medium,
PI. to the resistivity of the displacing media, P2, is greater than one, L.e., p,/p2> 1. a
stairstep curve similar to that shown In Figure 2 will result. For water displacing air In
the fracture, this ratio is much greater than one, and the change in signal response as the
water moves across the electrode grid Is very distinct. The general trend will be a
decreasing resistivity. This same case, L.e., water flowing nto a dry fracture, will have a
ratio of dielectric constant less than one, and the capacitance curve will be an increasing
stairstep as shown in Figure 2. The results considered are at a fixed frequency. There are
very definite frequency effects. By careful experimentation during the calibration
procedure, the frequency that will give the most distinct signature will be found. The
expected frequency range is 5-1000 Hz (7).
If all the fingers are of equal length and greater than the grid separation, then one
should obtain a characteristic curve that will predict the velocity of the fingers and of the
front the length of the fingers, and the areal fraction occupied by the fingers. In Figure
3, an idealized response curve Is shown. Here, At1 is the time taken by the fingers to go
from the first grid to the second grid, Atf is the time taken for just passage of the
fingers until the main body of fluid, (fluid bank), encounters the first grid, and At2 Is the
time required for the bank to pass through the grids. Then, if I is the separation of
-II-
RESPONSE
pi >I andC 2 P 2
C2
P1
fl
EX: WATER FLOWING INTO A DRY FRACTUREI
5:
FnI
a.
C.)TIME TIME
Figure 2. Response to be Expected for Idealized Frontal Instabilities
h no -k
ml 6 '
I q
wUz
a.4 1
I t1 Iatf I at2
%=
IVb =a
XAt2
If = I Vf,6tf
TIME
Figure 3. Definition of Times Associated with Frontal Instability Measurements
the grids,
velocity of fingers = Vf = I/Atl,
velocity of bank = Vb = /At 2, and (2)
length of fingers = If = I + VfAtf.
In the simplest case the areal fraction, A, occupied by the fingers can be obtained
under the condition of fingers long enough to extend through both grids as shown in Figure
4. For measurements between the electrodes, the equivalent circuits are parallel
capacitors and resistors. Thus, the equivalent or effective capacitance, Ce, is given by
AC =C + C = (1-A)c + A (3)
e 1 2 4nffi 1 2
47riC - C -C
or A= e A = e b (4)- 7-a;C-2 1 a b
A A1 2
where C = , C - (5)b 4iri a 4wr
Note that (Figure 4) the values of Ca, Cb, and Ce can be read directly from the measured
capacitance response curves. Because the displaced fluid, with an areal fraction of (I-A).
acts like a resistor in parallel with the fingers of the displacing fluid, with an areal
fraction of A, it can be shown that
( -p)a b e (6)
A=( -)
e b a
-14-
AREAL FRACTION MODELS
-n AtMn-
Ul~ I flPis c1 ,C 2
771W717771F/P2 e2
A= CCbCa Cb
A= Pa [Pb Pe]
Pe [Pb -Pa]
5n
cu)cc
LaC.)z
I-
Ci)
0.ci
W- -Ca
Ce
rCb
TIME TIME
Figure 4. Computation of the Areal Fraction, W. Occupied by Fingers in anAdvancing Front
-15-
where Pa' pb, and pe are as defined in Figure 4, and the resistivity, p is given by
R*APi ii (7)
The reciprocal of the effective resistance, Re. is thus equal to the sum of the reciprocals
of the individual resistances of the fingers and the displaced fluid.
If the fingers are not of uniform length, or if they are not longer than the electrode
separation, the response curve will not show the sharp discontinuities and flat plateaus
that are depicted in Figure 2. The sharp corners will become more rounded, and the
discontinuities may become inflection points on the curves. For these cases, establishing
relationships between the impedance response curves and water movement and water
volume will provide information on the characteristics of the shape of the water front.
Establishment of Relationship between Impedance Response and Water Volume and
Movement
As mentioned in the above description of the LIMFF technique, the impedance
measurements will change as one fluid displaces another fluid with different electric
properties. The magnitude of the change will depend upon the relative magnitude of the
electrical properties (resistivity and dielectric constants). When water completely
displaces air, the impedance response can change by more than four orders of magnitude,
since the ratio of the resistivity of water to air is generally in the range of 102 _ O0
(depending upon the electrolyte concentrations in the water). The impedance response
will indicate the passage of the conducting fluid past the electrodes and indicate the
shape of the fluid front. To provide more detail about the front and the amount of water
-16-
moving past the electrodes, it is necessary to establish a relationship between the
magnitude of the impedance response and the water volume associated with it.
To establish this relationship in a controlled manner, a fracture will be simulated by
constructing two flat plates in a parallel arrangement with a spacing, or aperture, that
can be regulated and defined (see Figure 5). An electrode grid will be emplaced on the
interior surface of one plate using the same technique (see Appendix B) used on the
fractured tuff core samples to be used in the experimental tests described later in this
document. One plate will be made of glass to allow visual observation of fluid moving
through the simulated fracture, or crack. The sides of the flat-plate arrangement will be
sealed to allow fluid to run only through the ends. With water moving through the crack
and past the electrodes, a frequency-dependent map of and p can be made along the
length of the crack. The water moving through this simulated fracture will be at
temperatures and pH values similar to those of the water used in the experimental tests
that will be carried out using fractured tuff core samples. Both temperature and pH of
the fluid will affect the electrical-property readings. Pressures used in the experimental
testing will not be high enough to significantly affect the electrical-property readings.
The first test will be to check whether the electrode grid size has a surable effect
upon the flow behavior of water through a crack. With the aperture of the crack set to a
definable value of 20-100 jim (characteristic of the size of a closed fracture), water will
be allowed to flow through the crack, and impedance measurements will be made. The
electrode grid will then be removed from the flat plate and another grid emplaced,
decreasing the size and areal extent of the electrode grid. The plates will be reassembled
with the aperture set to the previous value, and impedance measurements will again be
-17-
FLOW OF WATERTHROUGH CRACKOF APERTURE e
-2
CERAMICPLATE
GLASSPLATE
SHIM OFTHICKNESS e
Figure 5. Simulated Fracture
-18-
made. The electrode grid size will be decreased until no significant change in the
impedance measurements, and thus in the fluid flow behavior, Is detected. This grid size
will be assumed to be suitable for emplacing on the fractured samples.
To provide a relationship between impedance measurements and water volume, the
aperture of the crack will be varied and impedance measurements taken as water flows
past the electrodes. A certain volume of fluid between two electrodes will yield a certain
electrical impedance value. Since the dimensions of the crack aperture will be known, the
volume of water will be known and can be correlated with the impedance response.
Therefore, during experimental tests on fractured core samples, the volume of water
between two electrodes on the fracture surface can be determined from the value of the
impedance response.
If the shape of the water front, as it passes through the discrete fractures in the
tuff core samples, cannot be approximated by the idealized case discussed previously, it
will be necessary to develop a correlation between the impedance responses and the fluid
front development. The need for this will not be known until after testing the core
samples and evaluating the Impedance responses. To provide this relationship, the parallel
plates can be set at various orientations to induce different patterns of fluid flow. For
example, when the plates are set in a vertically upright position, with flow perpendicular
to the grid, the fluid front will have a symmetric, parabolic velocity distribution moving
past the electrodes. With the plates set at an angle, the shape of the front that moves
past the electrodes will change, with a corresponding change in the impedance response.
I he surface of the plates can also be physically altered by adding obstructions to flow to
induce various fingering effects. A visual (photographic) record of the fluid movement
-19-
can be made through the glass plate, and the shape of the fluid front can be correlated to
the impedance response. These correlations can then be used to infer the shape of the
fluid front in the core samples from the impedance measurements. The extent of the
procedure to correlate fluid-front development with impedance response will depend upon
the experimentally determined impedance responses obtained as fluid moves through the
fractured tuff core samples, the variation in the correlation between fluid front
development and impedance response, and the resolution that is deemed necessary.
-20-
TEST DESCRIPTION
Tuff core samples from various depths of USW G-4, containing a single, discrete
fracture, will be tested (see Table 1 for sample depth and unit description). The fracture
in each sample generally runs approximately axially through the middle of each core.
Some or all of these samples will be tested, with the possibility of adding other samples,
based upon experimental results and data needs. A series of experimental tests will be
run consecutively on the core samples selected for testing.
The core samples will be enclosed n a pressure vessel capable of providing confining
pressures up to 3000 psi (200 bars) and temperatures up to 2251C. with the pore fluid able
to enter either the top or bottom of the sample as desired. As shown in Figure 6a, the
test specimen will sit on a metal cylindrical platen and be constrained inside the pressure
vessel by a core holder assembly that will allow the pore fluid to move in and out of the
sample and that will allow for electrical wire leads to be attached to the copper electrode
grid emplaced on the fracture surface. An Illustration of the core holder assembly and
the electrode grid on the fracture surface is shown in Figure 6. The end platens and
porous stones will allow the pore fluid to enter and leave the core sample, and the
fluorosillcone sealant will insure that no fluid leaks down the side of the sample or leaves
through the sides of the core. The sealant will also keep the confining fluid from entering
the sample. The wire leads will be attached to each electrode in the grid pattern to allow
monitoring of the impedance measurements as water moves past the electrodes.
-21-
TABLE I
Sample Specification
USW G-4 Depth of Sample (ft) Unit Unit Description
1114 II-L Moderately to densely welded,devitrifled zone of the TopopahSpring Member of the PaintbrushTuff that contains more thanapproximately 10%, by volume.of vugs (voids in rock.)
1215 11-NL Moderately to densely welded.devitrified zone of the TopopahSpring Member of the PaintbrushTuff that contains less thanapproximately 10%, by volume, ofvugs. This is the proposedrepository unit.
1278 I-NL (See above)
1360 III Nonwelded-ashflows, bedded andreworked tuffs, vitric andprimarily nonzeolitized, from theTopopah Spring Member and/or theCalico Hills.
1551 IV-A Nonwelded ashflows, bedded andreworked tuffs, primarilyzeolitized, from the TopopahSpring Member and/or the CalicoHills.
1778 IV-C Upper zeolitized zone of theProw Pass Member of the CraterFlat Tuff.
-22-
0 U'v
W I 4
UPPER PLATEN_.
FRACTUREICORE
SAMPLE
FLUOROSILICONESEALANT -
V.
Figure 6a. Core Sample Encased in Core Holder Assemblywith Cutaway View of the Fracture Surface
Figure 6b. Electrode Grid Pattern on theFracture Surface
For the first test, water will be input slowly from the bottom of the saturated
sample. The sample will have been saturated (see Appendix A) prior to placement in the
pressure vessel to prevent any water from moving from the fracture into the matrix
because of capillary forces during testing. By utilizing the impedance measurements, to
monitor the water movement up the fracture utilizing the impedance measurements. the
flow rate, and thus the volume of water in the fracture, can be determined between
electrode pairs. The total fracture volume can also be determined by monitoring the
input flow rate and the total time required to reach the top of the fracture. From the
length and width of the fracture, an average fracture aperture (geometrical) can be
determined as well as an estimate of the geometrical aperture change along the core
length. The test will be run at approximately 6-10 effective confining pressures in the
range of 15-2250 psi (1-150 bars). The fracture will be cleared of excess water after each
test by blowing saturated air through the fracture. This test should give the fracture
aperture as a function of the applied confining pressure along the fracture length, as well
as give a more complete characterization of the fracture geometry.
The second test series will be a conventional permeability test with the water inlet
flow rate at the top of the sample at a velocity greater than the expected saturated
conductivity. The flow rate and pressure drop across the sample will be measured when
steady state is achieved. Using a similar experimental configuration, Pacific Northwest
Laboratories (9) has measured saturated fracture permeabilities as a function of effective
confining pressure for five fractured tuff core samples and shown that the fluid flow rates
vary more than three orders of magnitude among the core samples tested. In this test
series, the confining pressure will be varied as in the first test to produce changes in the
fracture aperture. These permeability data, with the aperture known as a function of the
-24-
confining pressure, will indicate the validity of the "cubic law" model for fracture
permeability by comparing the average aperture determined by the previous test with that
calculated using the model. Barton et al. (4) have shown that the measured geometric
aperture may be significantly different from the smooth-wall, hydraulic aperture
predicted by the "cubic law" model. At each effective confining pressure, the pressure
drop across the sample will be varied to give the flow rate as a function of pressure drop.
The range of the pressure drop and the number of values tested will depend on a particular
sample and Its fracture permeability and will be determined during the test. Knowledge
of the relationship between pressure and flow rate will Indicate the validity of assuming
Darcian flow for water movement In fractured tuff samples. Tests recently performed by
Evans (10) on a sample of granodiorite containing a single natural fracture Indicated that
the flow was generally transitional between Darcian and wholly turbulent flow. These
tests will also be run with the water velocity at various fractions of the measured
saturated conductivity value and the moisture history monitored along the fracture. The
moisture history, as determined by the impedance measurements, will Indicate the nature
of flow and the effects on flow of channeling or fingering, If they occur.
The sample will then be dehydrated using a vacuum drying process (see Appendix A).
With the sample matrix dry, the open fracture will be filled with water and no water
allowed to leave or enter the fracture through the end platens. Impedance measurements
will monitor the movement of water from the fracture nto the matrix as capillary forces
draw water Into the dry matrix. After all, or a significant portion, of the water has
moved into the matrix, leaving a relatively dry, drained fracture, the fracture can again
be filled and the water movement into the matrix monitored. As the matrix saturation
Increases, this rate of transport should decrease. A rate of water transport between the
-25-
fracture and the matrix can be determined as a function of the saturation of the matrix.
This will indicate the natural saturation condition of fractures underground at various
matrix saturations.
Saturated permeability tests will also be performed to determine the permeability
(and fracture aperture) response to temperature. These tests will generally be done last,
because the sample must be heated through the use of a heating jacket that can be
attached to the pressure vessel and there Is an increased possibility of leaks around the
sample at increased temperatures due to increased stresses on the sealant encapsulating
the sample. With the confining pressure set initially at the desired constant value (the
simulated In-situ pressure s 0.97 psift x sample depth), the temperature will be gradually
stepped up, the sample allowed to reach steady state, and the permeability determined.
The test will be repeated at higher temperatures, up to a maximum of 2250 C. This
information will yield the fracture's permeability response to a temperature change,
which is needed for near-field calculations.
When a test series has been completed on a core sample, the surface roughness
characteristics of the discrete fracture can be determined using a profilemeter to show
the deviation of the fracture's surface from a planar crack. The need for this information
will depend on the nature of the flow behavior and the moisture history in the fracture as
determined by the impedance measurements during the various tests. This surface
topography information may be necessary to understand channeling, If it occurs.
-26-
EXPECTED RESULTS
With the theoretical development of flow in natural fractures in its Initial stages and
the sparsity of data concerning the flow of water in fractured rock masses, there is an
essential need for hydrological measurements on fractured rock samples. The
experimental series planned Is an initial laboratory effort to provide qualitative and some
quantitative information on the characterization of fluid flow In discrete fractures. While
specific results of the experiments cannot be defined a priori for a general set of tuff
core samples, some general expected results, as well as some of the data analysis methods
to be used, are presented here. The type of response expected from the impedance
measurements as water flows past the electrode grid on the fracture surface, as well as
methods for interpreting the data, are presented in Section 3 and are not repeated here.
The fracture aperture, and thus the saturated conductivity, are expected to change
with the applied stress (effective confining pressure), decreasing asymptotically as the
pressure increases. The rate of decrease will depend on the characteristics of a particular
fracture, but experimental data for other rock types Indicate that the following functional
forms may be useful in describing the change of the aperture and saturated conductivity
as a function of the effective confining pressure (see,.e.g., Figures 7 and 8, and 9):
b = cI- C2*ln(Pe)f] (Ref 14) (8)
k/k* = A + * (-n) (Ref II) (9)
(k/k*)1/3 = D - E~ln(pe) (Ref 14) (10)
-27-
0.012
0.010
I0
w
w
1 L0cL.4
0.008
0.006
0.004
0.002
0.0000 10 20 30 40 50 60 70 80 90 100 110 120
EFFECTIVE PRESSURE (bars)
Figure 7. Fracture Aperture Versus the Effective Confining Pressure
" , w .,
I * 4 O e a
I I I I I I I AlI I I
1*0 ads o ~~PNL EXPERIMENTAL DATA[8
k/k*0-0.081 p513 +1.22
0.6
LU 0
0.4
Nu-I SAMPLE DEPTH 1215 ft., USW G-4
~0.2
0z
0 .0IIII II0 10 20 30 40 50 60 70 80 90 100 110 120
EFFECTIVE PRESSURE (bars)
Figure 8. Normalized Fracture Permeability Versus the Effective Confining Pressure
"NOJ
a.
co
0LuICM
NI
~1
0z
1.0
0.8
0.6
0.4
0.2
I I I I I I I I I I
o PNL EXPERIMENTAL DATi
- k/k=1.588-0.258 In (pe)0
0~~~~~~~~~
SAMPLE DEPTH 1215 ft., USW G-4
I I I I I I I I I II
k[8]
VI0
0
0.00 10 20 30 40 50 60 70 80 90 100 110 120
EFFECTIVE PRESSURE (bars)
Figure 9. Normalized Fracture Permeability Versus the Effective Confining Pressure
I ,. X,
where:
b = fracture aperture
k = saturated fracture permeability
k* = an arbitrary reference permeability
Pe = effective confining pressure
P(confining fluid) - P(pore fluid)
c1,c2,A,B,DEn = constants
With the fracture aperture measured or estimated as a function of the effective
confining pressure, these equations can be used to determine the permeability as a
function of the aperture. These experimental results will be used to determine the error
Involved in using the "cubic law" model with assumed Darcian flow for determining the
fracture conductivity and thus the flow in a fracture. The "cubic law" model for a single
fracture gives:
3
-b D W 1 (1 1)q 121
where:
q = water flow rate
IL = viscosity
p = density
g = gravitational constant
W = fracture width
I = hydraulic gradient
The assumption of Darcian flow can be checked by plotting flow rate versus the hydraulic
gradient. If the plot Is linear, Darclan flow is a valid assumption: if non-linear, it
indicates that the flow regime Is between Darclan and turbulent flow.
-31-
Data on the fracture saturated conductivity and aperture response to temperature
are scarce, with the phenomena involved not well understood. Experiments done to date
by other researchers have been done almost exclusively using sandstone at low pressures.
which gives little information on the expected response of tuff. For a discrete fracture in
a tuff core sample of essentially constant volume, it is expected that the permeability
will decrease because of thermal expansion but increase because of the changes in the
viscosity of water. Which effect will dominate is not apparent. There does not appear to
be any functional relationship for fracture-conductivity response to temperature, largely
because of the lack of data on any rock type and the subsequent lack of analysis.
With no previous laboratory evidence to suggest the nature of the moisture content
and fracture conductivity as a function of suction head, there have been no postulated
functional forms to describe these curves. It is not even known if an unsaturated flow
condition can exist in a fracture (other than film flow), with some researchers suggesting
an on-off' mechanism where flow can occur when the fracture is fully saturated and no
continuous flow occurs at all other levels of saturation. If information about these curves
can be deduced from observing the water movement in the unsaturated fractures, it is
expected that the data will yield a characteristic curve resembling a step function.
The general lack of data and understanding of the phenomena involved in fracture
hydrology makes the results difficult to anticipate. General results that can be expected
and some methods for data analysis have been presented, with the information from the
experiments serving to direct further analysis.
-32-
EXPERIMENTAL APPARATUS CONFIGURATION
General Description
The experimental apparatus is designed to measure water movement through core
samples at above-ambient pressures to monitor the flow characteristics of water through
a fractured rock. The individual components are, in general, off-the-shelf equipment
with modifications specified to suit experimental needs. The electrode grid applied to the
fracture surface and the core holder were designed in-house. The basic experimental
apparatus and configuration are similar to pressurized permeability apparatus used by
other Investigators (9,11,12), with modifications made to support the operating conditions
and instrumentation needs for the planned fracture flow experiments. The core sample to
be tested will be placed in a pressure vessel capable of providing for a confining pressure
of up to 3000 psi (200 bars) to be applied to the sample. This will be adequate to simulate
the in-situ pressure condition of the samples to be tested. The core samples will be
physically Isolated from the confining fluid by coating the samples with a fluorosilicone
sealant. The core holder assembly that supports the core sample is shown in Figure 6a.
The pore fluid, water, will be able to enter through either end of the sample in the
pressure vessel and can be pressurized to give pore pressures up to 750 psi, which is
greater than the anticipated in situ pore pressures of the rocks to be tested. A schematic
diagram of the experimental apparatus and configuration to be used is shown in Figure
10. The specifications of the major equipment and instrumentation components are listed
in Table 2.
-33-
I
PORE WATERCOLLECTION
@ FLOW METER0 REGULATING VALVEo METERING VALVE0 CHECK VALVEo PRESSURE GAUGEo VACUUM GAUGECM FILTER0 PRESSURE RELIEF VALVE
PORE FLUID INLET/OUTLET
Figure 10. Fracture Flow Experimental Apparatus Schematic
0 4. A
Table 2
Equipment and Instrumentation Specification
Description
Structural Behavior EngineeringLabs Corp., modified Rockwellmodel 10 pressure vessel.
Haskel nc., air-driven liquidpump, model DSF-25(confining fluid pump).
Haskel Inc., air-driven liquidpump, model DSF-B22(pore fluid pump).
Hydrodyne Corp., bladderaccumulators (water or oil)model BR30-60WS.
Flow Measurement Systems, Inc.,(2) fluid flow meters, modelFMT-N.01-L410 and Indicator/Totalizer, model PC402AAIL.
Precise Sensors Inc.. (2) sealedpressure transducers, model 6540(for differential pressuremeasurement across sample).
Precise Sensors Inc., (2) sealedpressure transducers, model 6540and indicating system, model455-FR-3000-01 -S-BD 10-BC0-Q.
(2) vacuum pumps.
Specifications
Max. Working Pressure: 3000 psiProof tested to 10,000 psiHeating Jacket Assembly to controltemperature to 4250 C 14 fusite feed thrusand 2 25-pin connections forinstrumentation.
Max. outlet pressure: 4000 psiMax. flow rate 2000 psi:400 cubic inches/min
Max. outlet pressure: 3200 psiMax. flow rate @1000 psi:775 cubic inches/min
Max. working pressure: 3000 psiCapacity: 1 quart
3Flow rate range: 4-60 cm /minOperating temperature: 60-4000 FMax. working pressure: 2500 psi
Operating pressure: 0-750 psiCombined non-linearity andhysteresis: (0.5% FSOOperating temperature: 60-3500 F
Operating pressure: 0-3000 psiCombined non-linearity andhysteresis: (0.25% FSOOperating temperature: 60-3500 F
Max. vacuum: 0.01 Torr
Omega Corp., digital temperatureindicator for type K thermocouples,400 series.
Hewlett Packard Impedance AnalyzerModel II HP4192ALF.
Operating temperature range:-133 0 C - >10000CAccuracy: 10C
Frequency Range: 5 Hz-13 MHz.
-35-
Table 2 (cont'd.)
Equipment and Instrumentation Specification
Hewlett Packard HP85B computer.
Hewlett Packard DigitalVoltmeter, Model 3456A.
Hewlett Packard data acquisition/control unit (scanner) Model 3497A.
Enhanced basic language Dual disk drives,500K byte capacity/disk 62650 bytesread/write memory
100 nanovolt sensitivity at48 readings/sec with 6.5 digitresolution; HP-IB compatible
Digital or analog control,includes real-time clock,1 micro-volt sensitivity withreading rates to 300/sec
-36-
System Components
Pore-Fluid Loop
Water will be used as the pore fluid and will be deaerated using a vacuum pump to
reduce errors in instrumentation responses due to trapped gases in the fluid. The water
can be pressurized up to 750 psi by an air-driven liquid pump manufactured by the Haskel
Corp. The pump is driven by gas pressure up to 150 psi to be provided by a combination of
house air pressure and bottles of compressed air or nitrogen. The pump automatically
ceases pumping (stalls) at the pressure preset by adjustment of the air-drive pressure
control. A bladder-type accumulator manufactured by the Hydrodyne Corp. will help
maintain pressure and damp any pressure surges in the pore-fluid system. The pore fluid
then passes through a 65/35-micron, dual-disk filter. Flow meters, capable of measuring
fluid flow as low as 4 cm3 per minute will monitor the inlet fluid flow rate upstream from
the pressure vessel and the effluent flow rate after the fluid leaves the pressure vessel.
Valving will allow the pore fluid to bypass the upstream flow metering system,
manufactured by Flow Measurement Systems Inc.. when the flow rate exceeds 60 cm3 per
minute. This is the maximum flow rate the flow meters can measure without the
possibility of damage to the instrumentation. The system is valved to allow the inlet pore
fluid to be directed to either the top or the bottom of the test specimen and the outlet
pore fluid to leave from the remaining end. The tests to be performed require the option
of having the pore-fluid inlet at either the top or bottom of the sample. Just before the
pore fluid collection system, the pore water wkill be valved to allow the bypass of the
outlet flow metering system, also manufactured by Flow Measurement Systems, Inc. Fine
metering valves will be used to control backpressures at the pore-fluid exit. The
pore-water collection system will consist of either a volumetric or gravimetric system,
depending on the experimental requirements. A vacuum pump incorporated into the
-37-
pore-fluid loop will aid in the drying of the test specimen without removing it from the
pressure vessel. Pressures will be monitored at the inlet and outlet of the pressure vessel
with differential pressure transducers manufactured by the Precise Sensor Corp.
Confining-Fluid Loop
The confining fluid will be silicone-based and will be pressurized to the desired
confining pressure (up to 2500 psi) by an air-driven liquid pump manufactured by Haskel
Corp. The pump is driven by gas pressure up to 150 psi to be provided by a combination of
house air pressure and bottles of compressed air or nitrogen. The pump automatically
ceases pumping (stalls) at the pressure preset by adjustment of the pre-set air drive
pressure. A bladder-type accumulator manufactured by the Hydrodyne Corp. will help
maintain the confining pressure and will assist in damping pressure surges in the confining
fluid caused by the pumping action of the air driven pumps. The pressure of the confining
fluid will be monitored using a pressure transducer manufactured by the Precise Sensor
Corp. and the temperature monitored using a thermocouple.
Pressure Vessel
The pressure vessel, manufactured by Structural Behavior Engineering Labs, Inc.
(SBEL), is capable of withstanding confining pressures of 3000 psi. A heating jacket
attached externally to the pressure vessel has a capability to heat the core to 2250C. The
core samples to be tested, with dimensions of 5-7 cm in diameter and 5-15 cm in length.
will sit on a platen in the interior of the pressure vessel. To accommodate the
instrumentation to be attached to the sample, 14, 4-pole fusite pins internal to the
pressure vessel will be connected to two, 25-pin connectors incorporated into the design
-38-
of the pressure vessel. A port has also been added to accommodate a thermocouple to
monitor the confining-fluid temperature.
Instrumentation
A schematic diagram of the instrumentation system to be used is shown in Figure 1 1.
The specifications of the major instrumentation components are shown in Table 2. The
data acquisition/control unit (scanner) will be used to multiplex the signals from the
pressure, temperature, and fluid-flow instrumentation components to the digital
voltmeter. It will also multiplex the impedance measurements from the electrode grid on
the fracture surface to the impedance analyzer. The scanner provides control functions
through a real-time clock.
The digital voltmeter is needed to achieve high precision and accuracy in these
low-voltage-level measurements. Analog scanning rates of 330 channels/second can be
obtained between the scanner and the voltmeter. The voltmeter built-in memory allows
storage of up to 350 readings with a programmed time delay from 0 to 1000. This feature
allows efficient use of computer time for long measurement operations. Before the signal
enters the digital voltmeter, analog outputs will be made to a strip chart recorder and
indicators as visual aids to the operator.
Output signals from both the digital voltmeter and impedance analyzer will be
transmitted to a Hewlett Packard HP-85B computer which contains 64K bytes of memory,
of which 32K bytes are directly accessible as read/write memory. 1 he other 32K bytes
are electronic disk memory with print specifications 15 times faster than the flexible
disk. The response signals from the flow meters, pressure transducers, thermocouples,
-39-
0
ELECTRODEGRID
OUTPUTS
FLOW METERS
PRESSURETRANSDUCERS
DATAACQUISITION
-CONTROL UNIT(SCANNER)
IMPEDANCEANALYZER
HP-5B
COMPUTER
PLOTTER/PRINTER
i .
TEMPERATURETHERMOCOUPLES Z/ P-
DIGITALVOLTMETER
STRIP CHARTRECORDER
DUALDISK DRIVE
Figure 11. Instrumentation/Data Acquisition System
h .6
and impedance analyzer will all be monitored by the HP-85B computer and stored on
flexible disk using the dual disk drive.
The signals monitored will include signals from the pressure transducers measuring
the confining pressure, the upstream pore-fluid pressure, the differential pressure across
the sample, the confining-fluid temperature, the pore-fluid temperature, the upstream
and downstream fluid flow rates, and the electrical impedance measurements from the
electrode pairs on the fracture surface.
-41-
QUALITY ASSURANCE
The following measures are being instituted in an attempt to comply with the spirit
of the Organization 6310 Quality Assurance Program Plan (QAPP) dated 2/6/84. The QA
Chief has designated this work as Minor Level 111.
Quality Assurance Procedure (QAP)
A QAP was written to define quality assurance procedures for operation of the
experimental apparatus described in this document. A copy of the QAP is included in
Appendix C.
Safe Operating Procedure (SOP)
An SOP was written prior to the start of the experimental testing procedures. The
SOP provides procedures that facilitate safe operation. It also provides for test
procedures that can be repeated and referenced and can aid in achieving accurate and
precise data. A copy of the SOP is included in Appendix D
Identification and Control of Samples
Test samples will be controlled and documented before, during, and after the
completion of testing. All test samples will be stored in containers marked with their
hole identification and depth interval (feet) before and after testing. A sample
-42-
identification may be added to the hole and depth interval at the discretion of the
operator.
When the test sample arrives at SNL by direct shipment from the U.S. Geological
Survey core library, QAP XI-l 1 will be followed (13). For test samples received by means
other than direct shipment from the USGS, depth interval, hole identification, and a
sample Identification designation (optional) will be maintained in an SNL-issued
engineering notebook.
Control of Measuring and Test Equipment
Whenever possible, the SNL Measurements Standards Laboratory will calibrate and
recall for calibration the measuring and test equipment used in this system. If the SNL
Measurements Standards Laboratory does not possess the capability to calibrate a device,
the manufacturer's certificate of calibration, if referencable to a known standard, will be
acceptable. If this occurs, it will be the responsibility of the personnel operating the
system (as defined in the SOP) to have the equipment calibrated on an appropriate recall
basis. Calibration guidelines that will be followed on, the measuring and test equipment
are listed in Table 3.
-43-
Table 3
Calibration Guidelines -
Instrument
Data acquisition/control unit
Digital voltmeter
Impedance analyzer
Calibrator
Strip chartrecorder
Pressure transducerindicating system
Thermocouples
Temperature
indicator
Analytical balance
Flow meter/flow meterindicating system
Manufacturer
Hewlett Packard
Hewlett Packard
Hewlett Packard
Soltec
Houston Instrument
ModelNumber
3497A
3456A
4192A
6141
4990
CalibrationLocation
SNL Div. 7243
SNL Div. 7243
SNL Div. 7243
SNL Div. 7243
SNL Div. 3425
SNL Div. 7546
SNL Div. 7243
SNL Div. 7243
SNL Div. 3425
Flow Measure-ment System*
Frequencyof Calibration
6-month intervals
6-month intervals
6-month intervals
6-month intervals
12-month intervals
6-month intervals
12-month intervals
6-month intervals
12-month intervals
6-month intervals
Precise Sensors
Autoclave
Omega
Mettler
Flow MeasurementsSystems
TP4401-KTP4400-K
400-A
PC4400
FMT-N.01-L410/PC402AAIL
* Not capable of being calibrated at SNL and will be calibrated by the manufacturer, withdocumentation as to this referencable calibration using Nationl Bureau of StandardsProcedures.
-44-
Sample Preparation
Any physical treatment that the test sample is exposed to will be documented in an
SNL-issued engineering notebook. Procedures designed to obtain the desired moisture
content of the test samples and processes used in preparing the sample and core holder
are documented in Appendix A.
Quality Assurance Records
At the end of each quarter in which testing has occurred, all test data are to be
copied and sent to the Org. 6000 QA Chief. A cover letter verifying that the contents
have been furnished will be sent with the data. The Org. 6310 Department Manager and
Org. 6313 Division Supervisor will be on distribution of the cover letter (without
attachments). At the end of each month, copies of the data stored on floppy disks will be
duplicated and kept In a separate location from the original test data.
System Function Verification
Before testing of a sample, there will be a two-part system function verification to
check the electrical characteristics of the electrode grid pattern on the fracture face and
to check the instrumentation/computer system electronics.
After the core holder has been assembled and electrically connected to the fusite
connectors In the pressure vessel, the electrical characteristics of the electrode grid
pattern will be checked using the system digital voltmeter and the results recorded in an
-45-
SNL-issued engineering notebook. To verify that the instrumentation/computer system is
functioning properly, the Soltec Calibrator will be used to input a known voltage to the
scanner. The voltage will be fed through the entire instrumentation system and be -
recorded by the computer. Any voltage drop or other electrical problems in the system
should be exposed during this procedure. The results will be recorded in an SNL
engineering notebook.
-46-
SAFETY
A Pressure Safety Analysis Report (PSAR) on the Division 6313 fracture flow
apparatus has been written to meet the SNL Pressure Safety requirements and has met
the necessary approvals. A copy of this report is included in the SOP in Appendix D.
The SNL Division 6313 Pressure Safety Advisor and Division 3441 Safety Engineering
consultant will personally inspect the system prior to Its operation.
-47-
SUMMARY
In a fractured rock formation, such as the Topopah Spring member of Yucca
Mountain, much of the information necessary to model the water movement using
computer codes must be obtained through small-scale or laboratory experimental
measurements; little of this information is available for the fractured tuff of interest to
the NNWSI project. The purpose of this work is to develop an experimental apparatus that
will enable us to increase our understanding of flow characteristics in a natural, discrete
fracture and, through this knowledge, to increase our ability to estimate the water
movement through a fractured tuff unit. The experiments described in this document are
an initial laboratory effort intended to ascertain the important parameters needed for
modeling. In addition to qualitative information, the experiments can provide needed
quantitative hydrological data: the determination of the fracture permeability at various
confining pressures is needed for estimating the saturated conductivity of a volume of
rock mass at various depths, and information on the fracture permeability response to
temperature is needed for modeling the repository near waste canisters. The results of
these experiments will also provide direction for future efforts to obtain the information
needed for modeling.
-48-
REFERENCES
1. Zimmerman, R.M., and Vollendorf, W.C., "Geotechnical Field Measurements,G-Tunnel, NTS," SAND81-1971, Albuquerque: Sandia National Laboratories, May1982.
2. Richards, L.A., "Capillary Conduction of Liquids in Porous Mediums," Physics, 1,318-333, 1931.
3. Barton, N., Bakhtar, K., Woodhead, S., and Bush, D. (Terra Tek Enginnering), "JointCharacterization and Modeling at NTS C-Tunnel," TRE83-40, 1983.
4. Freeze. R.A., and Cherry, J.A., Groundwater, Prentice-Hall. Inc., 39-43, (1979).
5. Memo from M.J. Martinez to L.D. Tyler, Sandia National Laboratories, "PreliminaryStudy of Moisture Transport through Unsaturated Fractured Porous Media," March15, 1983.
6. Eaton, R.R., Gartling, D.K. and Larson, D.E., "SAGUARO - A Finite ElementComputer Program for Partially Saturated Porous Flow Problems." SAND82-2772.Albuquerque: Sandia National Laboratories. July 1982.
7. Wayland, J.R., and Lee, D.O. (editors), "Sandia Heavy Oil Subprogram FY82 AnnualReport," SAND83-0117, Albuquerque: Sandia National Laboratories, April 1983.
8. Blair, S.C., Heller, P.R., and Gee, G.W. "Fracture and Matrix Permeability andRelated Matrix Properties of Five Core Samples of Tuffaceous Materials from theNevada Test Site," Letter Report to Sandia National Laboratories. January 1984.
9. Evans, D.D., "Unsaturated Flow and Transport through Fractured Rock Related toHigh-Level Radioactive Waste Repositories," University of Arizona. NRC ProgressReport, September 1983.
10. Nelson, R.A., "An Experimental Study of Fracture Permeability in Porous Rock,"17th Symposium on Rock Mech., 2A6-l - 2A6-8. (1976).
11. Counsil, J.R., "Steam-Water Relative Permeability," Dissertation, StanfordUniversity, (1979).
12. Peters, R.R., Klavetter. E.A., Hall. I.J., Blair, S.C., Heller, P.R., Gee, G.W.,"Fracture and Matrix Hydrologic Characteristics of Tuffaceous Materials fromYucca Mountain, Nye County, Nevada," SAND84-1471, Albuquerque: SandiaNational Laboratories, December 1984.
13. Schwartz, B.M., "Quality Assurance Procedures for Operation of the SNLA NNWSICore Library," QAP XI-l 1. February 1984.
14. Walsh, J.B., "Effect of Pore Pressure and Confining Pressure on FracturePermeability," Int. J. Rock Mech. Sci. & Geomech. Abstr.. 18, 429-435, (1981).
-49-
15. Memo from B.M. Schwartz to F.B. Nimick, Sandia National Laboratories,"Determination of Vacuum Saturation Procedures for Densely Welded Busted ButteOutcrop NX-Size Test Specimens," July 21, 1983.
16. "Standard Methods for Laboratory Determination of Pulse Velocities and UltrasonicElastic Constants of Rock," ASTM Standards D-2845-69 (1976), Section 6.2.
17. Richard Chavez, written communication to B. M. Schwartz, Sandia NationalLaboratories, Photofabrication Section, February 1984.
-50-
APPENDIX A
Sample Preparation
-A-i-
Sample Preparation
A. Log In/Log Out
1. If the core sample arrives by direct shipment from the U. S. Geologic Survey atMercury, Nevada, log in/log out procedures per SNL QAP XI-I I (13) will befollowed.
2. Samples arriving by other means will be logged in and out through entries in anSNL Patent Notebook.
3. The sample history of the core samples prior to testing will be documented in anSNL Patent Notebook. This includes the mechanical, pressure/vacuum andthermal history of the sample as well as its exposure to solvents.
B. Machining of Samples
1. All machining of core samples will follow the requirements stated in Section 5.4of QAP XI- II.
2. Posttest samples and scrap will be handled per the requirements stated in Section5.6 of QAP Xl-l 1.
C. Placement of the Copper Electrodes on the Fracture Surface
A vacuum evaporation process will be used to emplace copper electrodes on onefracture surface of the test sample. The procedure is documented in Appendix B. Theelectrode thickness will be approximately 0.00025-0.00050 inches and the widthapproximately 0.1 -0.2 inches. The spacing between the electrodes will range from0.1-0.5 inches, as desired.
D. Soldering of the Instrumentation Wires to the Electrodes
To attach wires to the electrodes emplaced upon the fracture surface, a soldering ironheated to between 500 - 6000F will be used to solder insulated copper wire to thecopper electrodes. The solder to be used is a resin-core solder, containing anon-corrosive and electrically non-conductive flux residue. Gloves will be used at alltimes to reduce the chance of contaminating the sample. The use of degreasingsolvents will be avoided whenever possible to reduce any possible damage to theelectrodes.
E. Moisture Content of the Test Sample
1. Vacuum Saturation of Test Specimens
Vacuum saturation has proved to be a time effective method of saturatingnatural (geologic) materials and will be used on test samples which need to besaturated prior to testing. The vacuum saturation process for test samples willbe performed external to the pressure vessel after attaching the electrical leadsto the electrode grid. The procedure empirically derived by Schwartz (15) willbe followed and has been written to meet or exceed ASTM requirements (16) for
obtaining constant weight values during a saturation process. After vacuumsaturation has been completed, the surface of the test sample will be allowed todry and the adhesive sealant will be placed on the sample. The adhesive will becured in high humidity conditions, an electrical check made on the electricalconnections, and the sample then submerged in water. Final preparations priorto loading in the pressure vessel include sealing the porous stone end caps andplatens to each end of the test sample using an adhesive sealant.
2. Vacuum Dehydration of the Test Specimens
Vacuum dehydration Is used as a means of drying the test sample without heatingthe test sample above ambient temperatures. The test sample will be vacuumdehydrated either before the attachment of electrical wires and adhesive sealantusing a vacuum apparatus external to the experimental apparatus or after theprepared test sample is placed in the pressure vessel. Vacuum capabilityincorporated into the pore-fluid loop will be used in the case of the latter. Ineither case, a vacuum of less than 0.1 Torr will be used to dry the sample.
When a test sample is evacuated external to the experimental apparatus, it willbe weighed using an analytical balance until it is determined that it has beendried to constant weight. Care will be taken to maintain sample dryness using adessicator when possible until the test sample is loaded into the pressure vessel.
When a sample is vacuum dried while still within the pressure vessel, it is notpossible to determine its dryness by gravimetric analysis. Therefore, samples ofsimilar physical properties (bulk density and porosity) and dimensions will be usedto optimize the vacuum drying procedure within the pressure vessel. The actualtest sample will then meet or exceed the vacuum drying regime determined toobtain constant weight on the samples.
-A-3 - A-4-
APPENDIX B
Procedure for Placement of an ElectrodeGrid on Rock Samples
-B-1-
Procedure for Placement of an ElectrodeGrid on Rock Samples
1. Wash off excess dust and loose dirt from the fracture surface with water, using asoft brass brush.
2. Dry using soft paper towels and then using air.
3. Degrease (using Chloroethane Nu).
4. Wrap wire around sample for handling during electro-less copper process and duringelectroplating, making sure the wire does not touch the fractured surface of thecore samples.
5. Degrease again.
6. Electro-less copper deposition.6.0 Immerse core into heated (130F) Conditioner 1175 (a slight etchant)
for 5 minutes.6.1 Rinse thoroughly with water.6.2 Immerse core sample into ammonium persulfate for I minute.6.3 Rinse with deionized water.6.4 Immerse into 10% sulfuric acid for 1 minute.6.5 Rinse with deionized water.6.6 Place core sample in a 1000 ml beaker and fill with Cataprep 404 (a
catalytic preparation) and soak for 10 minutes.6.7 Remove Cataprep 404 from beaker and fill with Cataposit 44.
(a deposition solution) leaving rock core immersed for 15 minutes.6.8 Remove rock core from beaker and rinse.6.9 Immerse core into electro-less copper solution for 15
minutes and rinse.
7. Electroplate copper at 20 amps per sq.ft. for 15 minutes. Copper thickness shouldbe around 0.00025 inches.
8. Rinse.
9. Dry with air.
10. Draw line across fracture surface using "Pilot SC-UF" permanent ink.
11. Immerse plated core sample with inked lines in ammonium persulfate solution toetch excess copper off.
12. Remove residue ink with acetone.
APPENDIX C
Quality Assurance Procedure
-C-l-
QAP _X-12REV APAGE 1
Quality Assurance Procedure for Operation
of the SNL Division 6313 Fracture Flow Apparatus ,,4
.
Page 1 2 3 4 5 6 7 9 10 1 2 3 4 5 6Rev A A A A A A A A A A A A A A A A
Approved by:
Inihstigator ad uthorB. M. Schwartz, 6313
__a. x>.itPrincipal InvestigatorE. A. Klavetter, 6313
7 Division SupervisorJ. R. Tillerson, 6313
9. CKAIndependent Reviewer
D. C. Reda, 1512
. _i--- -l .;Dat
0 / _Date
Date
7/2 ̂/19Y/Date
/O- - YDate
.
Organi tion 6300 QA Chief
QAP KI-12REV APage 2
1.0 Purpose and Content of Document
1.1 Purpose
The purpose of this document is to define quality assuranceprocedures for operation of an experimental system investigating themovement of water through fractured rock samples. The work is beingperformed in support of the Nevada Nuclear Waste StorageInvestigation Program (NNWSI).
1.2 Content
The document will describe:
o Quality Classification Level (2.0)o Approval Requirements (3.0)o Personnel Qualifications (4.0)o Sample Handling (5.0)
a. Log In/Log Out of Samples (5.1)b. Machining of Samples (5.2)c. Sample Encapsulation (5.3)d. Moisture Content (5.4)e. Placement of Electrodes on Samples (5.5)f. Signal Output from Electrodes to Instrumentation (5.6)
o Equipment Specifications (6.0)o Calibration Guidelines for Instrumentation (7.0)
a. Calibration Checks Performed by the Experimenter (7.1)o Posttest Sample Storage (8.0)o Documentation Requirements (9.0)o Deviations from this QAP (10.0)o Experimental Apparatus Schematic (11.0)o References
2.0 Qualitv Classification Level
The level is minor (Level I) at the time of this writing.
3.0 Approval Requirements
The persons listed below shall review and approve this document.
(1) The author and investigator(2) The principal investigator(3) An additional reviewer with hands-on experience from outside the
department of the investigators(4) The division supervisor of the investigators(5) lhe QA chief of the investigators
QAP XI-12REV APage 3
4.0 PersonneL Qualifications and Requirements
4.1 Qualifications
Persons engaged In these activities shall have demonstrated capability inlaboratory and documentary skills by previous training and experience.
5.0 Sample Handling
The information in this section shall be entered into an experimental logbook unlessspecified otherwise.
5.1 Log In/Log Out of Samples
o If the sample arrives by direct shipment from the US Geological Survey atMercury, Nevada. Log In/Log Out procedures per QAP XI- 1 will befollowed.
o Samples arriving by other means will be logged in and out using hole anddepth interval identifications and/or outcrop/sample identification system.
o The history of samples prior to testing will be documented. This includesmechanical, saturation and thermal history as well as exposure to solvents.
5.2 Machining of Samples
o All machining of samples shall follow the requirements stated inSection 5.4 of QAP Xl-ll.
o Posttest samples and scrap shall be handled per the requirements ofSection 5.6 of QAP XI- 1.
5.3 Sample Encapsulation
o The methods and materials used to encapsulate the samples ie, adhesivesand tubing) shall be documented in a thorough manner.
5.4 Moisture Content
o The methods used to saturate and/or dry the samples, both prior to andafter entry Into the pressure cell, shall be documented in an experimentallogbook.
5.5 Placement of Electrodes on Samples
o The processes and materials used to emplace electrodes on the fracturesurfaces shall be documented in a thorough manner for each sample tested.
QAP XI-12REV APage 4
5.6 Signal Output From the Electrodes to Instrumentation
o The methods and materials used in signal output from the fracture face toinstrumentation shall be documented in a thorough manner.
Note: Subsections 5.5 and 5.6 pertain only to test samples which will be used intests where impedance measurements will be made. It shall be noted in theexperimental logbook which test samples impedance measurements will be made.
QAPREVPage
XJ-12A5
6.0 Instrumentation and Data Acauisition Specifications (See also Figure,Page 7 and Schematic, Page 15)
This table documents the specifications of instruments and the dataacquisition system used in these experiments.
w,
Description SPecifications
Pressure VesselStructural Behavior EngineeringLabs Corp., Modified RockwellModel 10 Pressure Vessel
Liquid PumpsHaskel, Inc., Air-DrivenLiquid Pump, Model DSF-25(confining fluid pump)
Haskel, Inc., Air-DrivenLiquid Pump, Model DSF-B22(pore fluid pump)775 cubic inches/min.
Fluid DampenersHydrodyne Corp., BladderAccumulators (water or oil)Model BR30-60WS
Flow MetersFlow Measurement Systems,Inc., (2) Fluid Flow Meters,Model FHT-N.0l-L410 andIndicator/Totalizer, ModelPC402AAIL
Pressure Indicating SystemPrecise Sensors, Inc., (2)Sealed Pressure Transducers,Model 6540 (for differentialpressure measurement acrosssample)
Precise Sensors, Inc., (2)Sealed Pressure Transducers,Model 6540, and IndicatingSystem, Model 455-FR-3000-01-S-BDlO-BCD-Q
Precise Sensors, Inc., (2)Sealed Pressure Transducers,Model 6540 (for differentialpressure measurement acrosssample)
Max Working Pressure: 3000 psiProof tested to 10000 psiHeating Jacket Assembly to controltemperature to 425*C 14 fusitefeed thrus and 2 25-pinconnections for instrumentation
Max outlet pressure: 4000 psiMax flow rate 2000 psi:400 cubic inches/min.
Max outlet pressure: 3200 psiMax flow rate 1000 psi:
Max working pressure: 3000 psiCapacity: quart
Flow rate range: 4-60 cm3/minOperating temperature: 600-400FMax working pressure: 2500 psi
Operating pressure: 0-750 psiCombined nonlinearity andhysteresis: <0.5% FSOOperating temperature:60*-350*F
Operating pressure: 0-3000 psiCombined nonlinearity andhysteresis: <0.25% FSOOperating temperature:600-350F
Operating pressure: 0-125 psicombined nonlinearity andhysteresis: <0.5% FSOOperating temperature:60*-350*F
A
QAP X-12REV APage 6
Description Specifications
Vacuum Pump Max vacuum: 0.01 Torr.
ThermocoupleOmega Corp.. DigitalTemperature Indicator forType K Thermocouples.,400 series
Data Acquisition Device for Elec-trode Grid Impedance MeasurementsHewlett Packard ImpedanceAnalyzer, Model 11 HP4l92ALF
Data Acquisition DevicesHewlett Packard HP85B Computer
Hewlett Packard DigitalVoltmeter. Model 3456A
Hewlett Packard DataAcquisition/Control Unit(Scanner). Model 3497A
Analytical Balance Accessories0 Haus Calibrated MetricWeight Set, SandiaCalibration. SNLA-390
Cravimetric MeasurementsMettler Analytical Balance,Model PC4400
Satorius Analytical Balance,Model 1020
Digital Multimeter (General Usaae)Keithley Digital MultimeterModel 177
Note: All electronic devices should beminutes prior to usage.
Operating temperature range:-1330C - >10000 CAccuracy: C
Frequency range: 5 Hz- 3 MHz
Enhanced basic language dual diskdrives. 500 K byte capacity/disk 62,650bytes, read/write memory
100 nanovolt sensitivity at4B readings/sec with 6.5 digitresolution; HP-IB compatible
Digital or analog control,includes real-time clock.1 microvolt sensitivity with readingrates to 300/sec.
30 gram - I kg
Toploading, 0.01 gramresolution
Toploading, 1.0 gramresolution
4 1/2 Digit displayluV/Digit andI m t Digit resolution
turned on (warmed up) for 30
-C-7-
Instrumentation/Data Acquisition System.
ELECTRODEGRID
OUTPUTS
. l,.t
QAP X-12REV APage 8
7.0 Calibration Guidelines: This table documents the required calibrationsfor instrumentation and data acquisition devices used in theseexperiments.
Instrument
Data Acquisition/Control Unit
Manufacturer
Hewlett Packard
ModelNumber
3497A
CalibrationLocation
SNL Div 7243
Frequency ofCalibration
6-monthintervals
Digital Voltmeter
ImpedanceAnalyzer
Hewlett Packard
Hewlett Packard
3456A
4192A
SNL Div 7243
SNL Div 7243
6-monthintervals
6-monthintervals
Calibrator Soltec 6141 SNL Div 7243 6-monthintervals
Strip ChartRecorder
Houston Instrument 4990 SNL Div 3425 12-monthintervals
Pressure Trans-ducer IndicatingSystem
Precise Sensors SNL Div 7546 6-monthintervals
Thermocouples Autoclave
Omega
TP4401-KT P4400-K
400-A
SNL Div 7243 12-monthintervals
TemperatureIndicator
SNL Div 7243 6-monthintervals
AnalyticalBalance
Mettler PC4400 SNL Div 3425 12-monthintervals
Flow Meter/Flow MeterIndicating System
Flow MeasurementsSystems
FMT-N.01-L410/PC402AAIL
Flow Measure-ment System"
6-monthintervals
Digital Multimeter Keithley 177 SNL Div 7243 6-monthintervals
Documentation of these calibrations will be maintained in a notebook by the experimenterand recordkeeping requirements defined in Section 10.0 of this QAP will be fulfilled.
*Not capable of being calibrated at SNL and will be calibrated by the manufacturer, withdocumentation as to this referencable calibration using National Bureau of StandardsProcedures.
QAP X-12REV APage 9
7.1 Calibration Checks Performed by the Experimenter
7.1.1 Flow Meters
Once per week on weeks that the flow meters are utilized, the flowmeters will have their total flow and flow rates checked. Thiscalibration check, as described below, will be performedgravimetrically using an SNL calibrated balance, time source, andweights. The calibration check data will be entered into anexperimental logbook.
7.1.1.1 Procedure for Flow Meter Calibration Check:
1. Turn the flow meter on and allow to warm up for at least 30minutes prior to usage.
2. Connect the analog outputs of the flow meter to a strip chartrecorder or another recording device listed in Section 6.0.
3. Have water flowing through the flow meter at a rate anticipatedto be approximately that of the next rock sample run.
4. Have tubing attached from the downstream end of thedownstream flow meter to a container located on a calibratedbalance (listed in Section 6.0).
5. With the water flowing at a steady rate into the container, notethe weight of the container simultaneously with the start of thestrip chart recorder and the taring of the flow meter. Record theweight.
6. After an amount of water similar to that planned for the test hasflowed through the meter, note the weight of the container andthe flow value simultaneously with stopping the strip chartrecorder. Record the weight.
7. Calculate the rates and totalized flow from the analog outputsand digital indicator.
8. Repeat steps 1-7 for all flow meters to be used.
7.1.1.2 Acceptance/Rejection Criteria
A flow meter is 'in-specification' when the total flow and the flowrate values are in error less than or equal to 2.5 percent from thegravimetric measured value. If the calibration check shows that theflow meter Is 'out-of-specification" then tests on a rock. sampleare not to be done until the problem is corrected and verified bysubsequent calibration checks.
-C-10-
QAP XI-12REV APage 10
7.1.1.3 Nonconformance Documentation
Any tests performed during the period that the flow meter(s) mayhave been out of specification shall be flagged accordingly usingnotations on all records where data are stored, Including laboratorynotebooks, strip charts, computer print-outs, and disks. The flowmeters shall be identified by their model and serial numbers.
7.1.2 Pressure Transducers
1 he pressure transducers are part of the pressure indicating systemdefined in Section 6. There are 6 transducer channels which aredefined in Section 7.1.2.2 and two "Delta P" channels defined inSection 7.1.2.3. The calibration check data and any adjustmentsmade to the electronics will be entered into an experimentallogbook along with reference to the procedures used in performingthe calibration check.
7.1.2.1 Procedures for Checking the Zero Readout and theCalibration Bridge (R Factor) (To be performed once permonth in months that the pressure transducers are utilized.)
Note: This procedure applies to pressure transducer Channels 1-6.
1. Apply a vacuum of approximately I torr to the pressuretransducers which are to be utilized during the course of themonth.
2. Move the "channel selector" button to the desired pressuretransducer channel. (Located on the front panel of the PreciseSensor, Inc.'s pressure indicating system)
3. The digital Indicator should read zero. If It does not, then turnthe "zero/fine zero" adjustment until it reads zero.
4. Depress the "calibration" button located on the front of thePrecise Sensor, Inc.'s pressure indicating system)
5. The readout on the digital indicator should match the R factor"within 0.25% of the value for the respective channel printed onthe SNL calibration sticker. If It does not, turn the "span"adjustment until the "R factor" displayed on the digital indicatorfalls within this range.
6. The signal from the analog outputs of the pressure transducersshould match the R factor" value for the respective channelprinted on the SNL calibration sticker when read from a digitalmultimeter or voltmeter listed in Section 6.0.
7. Repeat steps 1-6 until the zero values and "R factors" aredisplayed as they should be for two consecutive cycles.
-C-l1-
QAP XI-12REV APage I 1
7.1.2.2 Procedure for checkinQ the Ambient Pressure Readout (To beperformed once per week in weeks that the pressuretransducers are utilized). The ambient pressure will bedetermined just prior to this calibration check using amercury barometer.
Note: This procedure applies for Channels 1-6.
B. Slowly release the vacuum from the pressure transducers andallow the pressure to equilibrate at the ambient level for at least5 minutes.
9. Check each digital indicator channel according to the table belowwhich gives the acceptable variation from nominal (ambient) foreach channel.
Operating AcceptableChannel No. Range (Psi Variation (psi)
I 0-3000 + I2 0-3000 + 3 0-200 + 0.34 0-200 + 0.35 0-20 + 0.36 0-20 + 0.3
7.1.2.3 Procedure for Checking the "Delta P Readout (To beperformed once per week in weeks that the pressuretransducers are utilized)
Note: This procedure applies to Channels 7 and B. Channel 7 is the'delta P" for Channels 3 and 4. Channel B is the delta P" forChannels 5 and 6. (The procedure is followed after pressuretransducer gauges 3 - 6 are under a vacuum of approximately I Torr)
10. Move the pressure indicating device 'channel selector" button toChannel 7. The digital Indicator should read zero + 0.1 psi. Theanalog Output from Channel 7 should read 0 + 0.5 millivoltswhen read from a Digital multimeter or voltmeter listed inSection 6.0.
11. Move the channel selector" button to Channel 8. The digitalIndicator should read zero + 0.1 psi. The analog output fromChannel B should read 0 + 0.5 millivolts when read from a digitalmultimeter or voltmeter listed in Section 6.0.
7.1.2.4 Acceptance/Rejection Criteria
A pressure transducer is in-specification when Steps 7 and 9 ofSections 7.1.2.1 and 7.2.2.2, respectively, have been successfullycompleted.
-C-12-
QAP XI-12REV APage 12
A Delta P channel is in-specification when Steps 10 and 11of Section 7.1.2.3. have been successfully completed.
7.1.2.5 Nonconformance Documentation
Any tests performed during the period that the pressuretransducers may have been out of specification shall beflagged accordingly using notations on all records wheredata are stored, including laboratory notebooks, stripcharts, computer print-outs, and disks. The pressuretransducers shall be identified by their model and channelnumbers.
7.1.3 Calibration of the Laboratory Impedance Measurements forFracture Flow (LIMFF) System (This subsection pertains onlyto samples with emplaced electrode grids.)
A device will be fabricated to attempt to quantify the signaloutput from the electrodes to the Impedance Analyzer. Thedevice will simulate a fracture by using parallel plates witha definable volume. The calibration will consist of twoareas:
1. Establishment of the relationship of the magnitude of thesignal output with the volume of water between the twotested electrodes.
2. Establishment of the relationship between the transientimpedance response of an electrode pair and the shape ofthe fluid front.
The second calibration area is non-essential and is necessaryonly for more accurately interpreting the movement of waterthrough a fracture. It is important for understanding thebasic phenomenology involved in water movement through anunsaturated fracture with variable surface roughnesscharacteristics. As such, it will support general researchon water movement through fractures and is expected toprovide data that is qualitative in nature. The first areaof calibration is necessary for the quantification offracture aperture with the signal response. Thesecalibrations are necessary only for data reduction andanalysis and will in no way affect the measurement orrecording of the experimental data.
The following items shall be documented in an experimentallogbook:
o The method of fabrication of the calibration device;o A listing of all equipment used in measurements;o The actual data obtained from these runs; ando A description of the method(s) of the data reduction and
analysis. -C-13-
QAP XI-12REV APage 13
7.1.4 "Whole System" Calibration Check
This calibration check will attempt to simulate actual testconditions and verify that flow and pressure measurements areaccurate, as well as evaluating seals for leaks. This check will beperformed twice per year (during the time period ofexperimentation) and documented in an experimental logbook.
Description of device: A cylindrical core (5.525cm diameter x6.35cm long) was machined from aluminum. A hole was drilledthrough the center of the cylinder axially of the followingdimensions:
Length: 2.92 x 10-3 m L/d - 10Diameter: 2.71 x 10-4 m
This core" is to be mounted to the core holder using the sameflexible jacketing materials to those used on rock cores. Aconfining pressure will be applied to its circumferential surfacearea. Steady state pore fluid flow ranging from 4 to 60cm3 /minute will be forced through the capillary tube and theresultant pressure drop measured. The cylindrical core will beinspected by SNL standards to verify the capillary tube diameterprior to usage, and documented per Section 10.0.
The permeability of this device will be measured using flow metersand/or gravimetrically. If the permeability (k) obtained during thischeck deviates from the expected by greater than or equal to + 5%and the discrepancy cannot be attributed to faulty seals, thenSections 7.1.1.1 through 7.1.3 should be followed to assess theaccuracy of the flow and pressure indicating systems.
k(theoretical) = (r 2 /8) = 2.31 x 10-9 m2
where r = radius = 1.36 x 10-4 meter
Therefore: + 5% yields:
k minimum = 2.19 x 10-9 m 2
k maximum = 2.43 x 10-9 m2
7.1.5 System Function Verification (This section pertains only to sampleswith emplaced electrode grids)
Just prior to testing a sample, there will be a two-part systemfunction verification to check the electrical characteristics of theelectrode grid pattern on the fracture face and to check theinstrumentation/computer system electronics.
-C-14-
QAP XI-12REV APage 14
After the core holder has been assembled andelectrically connected to the fusite connectors in thepressure vessel, the electrical characteristics of theelectrode grid pattern will be checked using the systemdigital voltmeter and the results recorded in anexperimental logbook. To verify that theinstrumentation/computer system is functioning properly,the Soltec Calibrator will be used to input a knownvoltage to the scanner. The voltage will be fed throughthe entire instrumentation system and be recorded by thecomputer. Any voltage drop or other electrical problemsin the system should be exposed during this procedure.The results will be recorded in an experimental logbook.
8.0 Posttest Sample Storage
Posttest samples and scrap will be handled per Section 5.6 of QAP XI-llRev. A.
9.0 Documentation Requirements
9.1 Pretest
Prior to sample testing. a letter of criteria (LOC) shall be written tothe principal investigator and/or the investigator as defined on thesign-off sheet (page 1) of this document. The following list containsthe minimum requirements to be addressed in a LOC.
1) Description of Test2) Sample Identification and History3) Sample Preparation Requirements4) Sample Treatment Prior to Testing5) Reporting and Documentation Requirements6) Quality Assurance7) Sample Disposition
9.2 Posttest
At the end of each quarter in which testing has occurred. allcalibration and test data are to be copied and sent to the appropriate6313 file guide Including 6330 NNWSI CF. A cover letter verifying thatthe contents have been furnished will be sent with the data. The Org6310 Department anager and Org 6313 Division Supervisor will be ondistribution of the cover letter (without attachments). At the end ofeach quarter, copies of the data stored on floppy discs will beduplicated and kept in a separate location from the original test data.
100. Deviations
Any deviation(s) from these procedures will be documented in theexperimental logbook. -C-15-
FRACTURE FLOW EXPERIMENTAL APPARATUS SCHEMATIC
HOUSE AIR
I
PORE WATERCOLLECTION
@ FLOW METER0 REGULATING VALVE@ METERING VALVE(D CHECK VALVE0 PRESSURE GAUGE@ VACUUM GAUGECo FILTER0 PRESSURE RELIEF VALVE
I' W.0>P) lo) '
eq-l < oID
Hp > I
V-n
PORE FLUID INLET/OUTLET
1, , . ,, In
QAP XI-12REV APage 16
References
Schwartz, B. M., Quality Assurance Procedure for Operation of the SNLA NNWSICore Library". QAP XI-11 Rev A) February 13. 1984.
Schwartz, B. ., Pressure Safety Analysis for Fracture Flow Apparatus,"internal memo dated January 31, 1984.
Schwartz, B. M., "Safe Operating Procedure for Fracture Flow Apparatus at SNLBuilding 823, Room 4270. SNL SOP #17000 8410," dated 10/4/84.
Klavetter, E. A., Peters, R. R. and Schwartz, B. M., Experimental Plan forInvestigating Water Movement Through Fractures," SAND84-0468, SandiaNational Laboratories, Albuquerque, New Mexico. (In preparation)
-C-l/ - C-18-
APPENDIX D
Safe Operating Procedure
SAFE OPERATING PROCEDURE
FOR
FRACTURE FLOW APPARATUS
AT SNL
BUILDING 823 ROOM 4270
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22Page:
Revision: AAA AA AAA AA A A A A A A A A A A A A
The purpose of the Division 6313 Fracture Flow Apparatus is to
evaluate flow of water through fractured tuff rock cores in support of
the Nevada Nuclear Waste Storage Investigations (NNWSI) program.
Potential hazards include high-pressure fluids. whipping hardware, and
stored energy release.
T. 0. Hunter - 6310 Date 3442 Date
3. R. Tillerson - 6313 Date Don - 3442 ate
(Safety)
Written byB. M. Schwartz - 6313 Date T. J. Cabe - 6255 Date
(Pressure Safety Advisor)
1.0 General
This SOP is provided as a guide for use by personnel of the
NNWSI Geotechnical Projects. Division 6313, who are authorized to
operate theeFracture Flow Apparatus. Use of this document will help
ensure that operations are performed in a safe manner and that
hazards are minimized.
The Fracture Flow Apparatus is a high-pressure facility used to
evaluate fracture flow through tuff rock cores. A detailed
description of the apparatus is contained in the Pressure Safety
Analysis (PSA).included as Attachment 1 of this document.
This procedure will be reviewed once per year by persons in the
respective positions as defined on the sign-off page. Personnel
authorized to operate the facility will review this SOP as often as
necessary to ensure familiarity with these procedures, but not less
than once per year.
1.1 Authorized Personnel: The following personnel are authorized
to conduct tests using the Fracture Flow Apparatus:
B. M. Schwartz 6313
E. A. lavetter 6313
o One operator is sufficient during normal working hours
except where noted due to lifting of heavy objects.
o Two operators are required before or after normal working
hours and on weekends and/or holidays.
Barry Schwartz is responsible for any design changes, operation
of the apparatus and for all safety-related requirements. He will
see that the provisions of this SOP are observed and that all
operation, certification, calibration, and documentation
requirements are followed.
1.2 Visitors: The authorized operating personnel shall inform all
visitors of potential hazards within the testing area.
1.3 Safe Operating Procedure (SOP) Location: A copy of the SOP
shall be kept on the "safe" side of the safety shield for quick
access when necessary.
2.0 Hazards: The primary hazard source is the circulating fluid
(silicon oil confining fluid at < 3000 psi and water at < 750 psi).
Temperature of the fluids will be at ambient conditions for
operation under revision A of this SOP. A schematic of the entire
system including the pressure relief system for the apparatus is
shown in Figure 1. Potential hazards in the design of the system
are addressed in the PSA (Appendix A). Hazards associated with
operation of the apparatus are minimized if the operating procedures
in Section 6.0 are rigorously followed.
-D-4-
3.0 Other Precautions:
o The pressure cell weighs approximately 150 lbs. Care should
be exercised in handling it. Two or more people should be used to
remove the cell from its base. teel toed safety shoes shall be
worn during this procedure.
o The amount of time that the apparatus is at pressure shall
be kept to a minimum. Casual personnel shall be kept out of the
laboratory and operators shall stay behind the safety shield
whenever possible to avoid unnecessary risk.
4.0 Protective Equipment,
o Hose tie-downs: The hardware is fastened to the steel table
utilizing braces primarily'on the valves which are the major torque
points. Tie-downs are also located at fittings throughout the
tubing network. These devices should always be kept in place to
prevent injury from whipping action of loose hardware.
o The pressure relief valves (PRV) are of the in-line type.
Prior to usage, they have been checked for proper operation by
Sandia Labs Safety Division 3441 and are tagged to verify that this
check has been performed. The tag also indicates when this check
should be performed in the future. Any fluid flow downstream of the
PRVs is transported directly to heavy aluminum overflow canisters
located under the work table. Small holes at the top of the
canisters allow fluid in and prevent pressure buildup but will not
allow for any significant release of fluid to the room. There are
separate canisters for the silicone fluid and the water lines which
are clearly identified. The volume of each canister is much greater
than the amount of fluid that can exit the respective fluid loops.
Schematics of the fluid loops and the identification system used for
the PVs and the regulating valves are shown in Figures 1 and 2.
o Safety shield: A shield made of a lexan plate in a wood
frame will be stationed in front of the work table. The operators
will stay on the safe side of the shield whenever possible during
operation of the apparatus.
o Lexan safety plates are in place in front of and behind the
Ashcroft 0-1000 psi pressure gauge located in the pore fluid loop.
o A transparent safety box is to be used at the downstream
sides of valves P14 and P16. A non-glass container will be placed
inside this box as will a battery-operated analytical balance. A
feed-through at the bottom of the box will be connected to the pore
fluid loop overflow canister (sump). The fluid entering this box
will be at ambient pressure although possibly under high flow
conditions in case of accident.
-D-6-
o Protective clothing: Non-slip soled safety shoes are
provided and shall be worn by the operators whenever operating this
facility. Lab coats are provided for each operator to shield their
street clothing from contact with oils and adhesives. Safety
glasses shall be worn when operating components under pressure or
when connecting or disconnecting lines.
5.0 Emergency Procedures:
o Emergency shutdown: If a rupture occurs in the high
pressure system or a similar emergency occurs, shut the air pressure
off to the Haskel liquid pumps immediately. This is done by turning
the blue-handled Jamesbury valves off (horizontal position) on both
valve C (confining loop) and valve P (pore loop).
o Electrical power loss: There are no electrical connections
to these liquid pumps: therefore, in case of a power failure when
pressure indicating devices are not functioning it is still possible
to be generating pressure. Due to this fact, during a power failure
the run should be aborted and valves C1 and Pi closed per the above
emergency shutdown procedure.
o Loss of building water pressure: There is no connection to
the building water supply; therefore, no action need be taken due to
the loss of this utility.
o Loss of building compressed air supply: If the liquid pumps
are being driven by the building compressed air supply and the
supply is interrupted. the pumps will either work intermittently or
not at all. Since this could adversely affect the desired confining
fluid/pore fluid pressure ratio. the run should be aborted and
valves Cl and P1 closed per the above emergency shutdown procedure.
Tests run over an extended period should use compressed air from
individual gas bottles located in Room 4270. This will minimize the
chance of accidental air pressure loss to the Haskel liquid pumps.
o The emergency telephone number is 144. This number can be
used to report any medical or other emergency. Be sure to give your
name, location and nature of the emergency. If the emergency is
fire-related, call 117.
Fracture Flow Apparatus
I Authorized Operators
By y signature. I acknowledge I have read, understand, and
will follow these procedures.
Barry Schwartz 6 Date6313
Elmer Klavetter
D a I
Date6 313
6.0 OPERATING PROCEDURE FOR SNLA
FRACTURE FLOW APPARATUS (BLD. 823. RM. 4270)
Refer to the System Schematic (Figures 1 and 2) for component
identification.
A. Test Preparation (All Tests). Verify the following prior to
each test:
1. The top of the pressure cell is screwed down, hand tight and all
four 1/8" NPT plugs on the sides of the cell are in place and
tightened down.
2. All pressure transducers and flow meters are connected per
Figure 1 and cables are attached to the indicating devices.
3. All safety tie-downs are secure.
4. All PRVs per Figures 1 and 2 are installed and that their
pressure safety tags are up to date.
5. Overflow canisters (sumps) are empty of liquids and the proper
overflow tubing lead to each canister.
-D-10-
6. The accumulators have been filled with nitrogen gas to the
desired pressure. usually 2/3 the working pressure of the fluid
loop for maximum damping effect. Do not change the gas charge
to either accumulator after starting the procedures in
subsection B of this section.
7. The yellow safety plugs are secured into the gas inlet fittings
on the confining and pore loop accumulators.
8. There is sufficient compressed air bottle pressure to last the
duration of the test if the Haskel pumps are to be powered using
bottled air.
9. That silicone fluid will enter the confining fluid loop and
deionized/distilled water will enter the pore fluid loop.
-D-1I1-
B. Procedures for Operation of the Confining Pressure Fluid Loop.
Note 1.
Note 2.
Note 3.
Pressurization of the confining fluid loop is performed
prior to pore fluid loop pressurization.
Except when noted in parentheses. the closed position
of a valve is obtained by turning it clockwise and the
open position counterclockwise.
All Autoclave I'speedbite4 connectors are tightened 3/4
of a turn past finger tight.
1. Check that the rock sample, porous stones, and platens are in
place, have been sealed using silicone adhesive, and are
connected to the pore fluid inlet/outlet fittings.
2. Check that the o-ring and the threads on the pressure cell base
plate are well lubricated with anti-seize compound and that
there are no visible cuts or tears in the o-ring.
3. Lift the top of the pressure cell (2-person job) and place on
the baseplate. Tighten (clockwise) until the pressure cell is
together using hand pressure only.
4. Tighten all 4 of the plugs located in the pressure cell wall.
Three are located midway up the pressure cell. The one located
near the top of the pressure cell is used for bleeding air out
of the confining fluid.
-D-12-
5. Check that PRV 1 and 2 are properly installed and that the
tuiAng connected to the outlets are connected to the confining
fluid sump.
6. Close valves C1. C2 (counterclockwise), C5, P1 and P2
(counterclockwise)
7. Open valves C3 and C4.
B. Adjust the air pressure into the Haskel pump (labeled confining
fluid) to the desired air pressure not to exceed 150 psi.
9. Slowly open valve Cl.
10. Slowly open valve C2 (clockwise) watching pressure transducers
channels 1 and/or 2. When the pressure is between 50 and 100
psi, close valve C (counterclockwise) then crack open the
bleed plug on the pressure cell until any trapped gas is
removed and fluid starts to drip out. Retighten the 1/8-inch
NPT bleed plug.
11. Open valve C2 (clockwise) and pressurize slowly until the
desired operating pressure is obtained. not to meet or exceed
the lower rating of PRV 1 or PR 2.
12. Monitor the confining fluid loop pressure using pressure
transducer channels 1 and 2.
-D-13-
13. Check all fittings and connections for leaks. Abort the run
and follow the shutdown procedures (Subsection C) if a leak is
found.
-D-14-
C. Confining Fluid Loop Shutdown Procedures (To be performed only
after the sample pore fluid pressure is ambient)
1. Close valves C2 (counterclockwise). Cl. and C3.
2. Open valve C4.
3. Crack open valve C5. watching pressure transducer channels
1 and 2. The confining fluid should be drained into the
overflow canister (sump) at a slow and steady rate. The
confining fluid exits the pressure cell at orifice L2
(scribed on cell base by the manufacturer).
-D-15-
D. Procedures for Operation of the Pore Fluid Loop When the Inlet
to the Pressure Cell is R1 and the Outlet is R2.
Note 1. Do not proceed with pore fluid pressurization until
the confining pressure fluid loop procedure
(Subsection B) has been completed. The confining
fluid pressure must be greater than the ultimate pore
fluid pressure.
4w,
Note 2. Except where noted in parenthesis, the closed position
of a valve is clockwise and the open position is
counterclockwise.
Note 3. All Autoclave "speedbite" connectors are tightened 3/4
turn past finger tight.
Note 4. Steps 1-10 pertain to operation of the pore fluid
loop when the flow meter upstream of the sample is
closed.
1. Check that PVs 3. 4. 5. and 6 are properly installed and that
tubing is connected to the pore fluid overflow canister.
2. Open valves P3 or P4 so that water is sent to the Haskel pore
fluid liquid pump.
3. Close valves P1, P2 (Counterclockwise),P5. P6. Pe, P. Plo.
P11. P12. P13. P14. P15. P16. and P17.
4. Open valves P7 P, P16, and P17.
5. Crack open valve P1.
6. Adjust the air pressure into the Haskel liquid pump (labeled
pore fluid) to the desired air pressure (not to exceed 150 psi).
7. Slowly open valve P.
8. Slowly open valve P2 (clockwise) watching the Ashcroft pressure
gauge and pressure transducers channels 3 and 4. When the
desired pressure in the pore fluid loop has been obtained as
shown on pressure transducer channels 3 and 4 (not to meet or
exceed the lower rating of PRVs 3, 4. 5, and 6) slowly open
valve P10 then carefully adjust valve P2 until the sample is at
the desired pore pressure.
9. Adjust the setting of valve P16 until the desired back pressure
is obtained while monitoring pressure transducer channels 3 and
4. Collect the fluid output from valve P15 into a nonglass
beaker which is housed inside the transparent safety box.
-D-17-
10. Adjust valve P2 during the test as necessary to uaintain the
desired sample pore pressure.
Note: When the flow meter(s) are opened to liquid flow then Steps
11-15 should be followed to avoid damage to the flow meter
electronics. There is no danger of affecting the pressure
safety rating of these devices. Their use as calibrated
devices, however. may be affected by improper usage.
11. Close valves P7. P15. and P16.
12. Slowly open valve PS.
13. Slowly open valve P6.
14. Slowly open valves 15 and 16 or valves 13 and 14 (if the
flowmeter downstream from the sample is to be used).
15. Adjust the system pressure as desired using valves P2 and P14
or P2 and P16.
-D-18-
E. Procedures for Operation of the Pore Fluid-Loop When the Inlet
to the Pressure Cell is 2 and the Outlet is R.
Note 1. Do not proceed with pore fluid pressurization until the
confining pressure fluid loop procedure (Section B) has
been completed. The confining fluid pressure must be
greater than the ultimate pore fluid pressure.
Note 2. Except where noted in parenthesis, the closed position
of a valve is clockwise and the open position is
counterclockwise.
Note 3. All Autoclave speedbite"s connectors are tightened 3/4
turn past finger tight.
Note 4. Steps 1-10 pertain to operation of the pore fluid loop
when the flow meter upstream of the sample is closed.
1. Check that PVs 3, 4. 5, and 6 are properly installed and that
tubing is connected to the pore fluid overflow canister.
2. Open valves P3 or P4 so that water is sent to the Haskel pore
fluid liquid pump.
3. Close valves P1. P2 (Counterclockwise).-P5. P6, P6, P11, P12.
P13, P14, P15. P16 and P17.
4. Open valves P7, P9, P15 and P16.
-D-19-
5. Crack open valve P.
6. Adjust the air pressure into the Haskel liquid pump (labeled
pore fluid) to the desired air pressure (not to exceed 150 psi).
7. Slowly open valve P1.
8. Slowly open valve P2 (clockwise) watching the Ashcroft pressure
gauge and pressure transducers channels 3 and 4. When the
desired pressure in the pore fluid loop has been obtained as
shown on pressure transducer channels 3 and 4 (not to meet or
exceed the lower rating of PRVs 3, 4, 5. and 6) slowly open
valve P12 then carefully adjust valve P2 until the sample is at
the desired pore pressure.
9. Adjust the setting of valve P16 until the desired back pressure
is obtained while monitoring pressure transducer channels 3 and
4. Collect the fluid output from valve P15 into a nonglass
beaker which is housed inside the transparent safety box.
10. Adjust valve P2 during the test as necessary to achieve the
desired sample pore pressure.
Note: When the flow meter(s) are opened to liquid flow then Steps
11-15 should be followed to avoid damage to the flow meter
electronics. There is no danger of affecting the pressure
safety rating of these devices. Their use as calibrated
devices. however. may be affected by improper usage.
-D-20-
11. Close valves P7, P15, and P16.
12. Slowly open valve PS.
13. Slowly open valve P6.
14. Slowly open valves 15 and 16 or valves 13 and 14 (if the flow-
meter downstream from the sample is to be used).
15. Adjust the system pressure as desired using valves P2 and P14
or P2 and P16.
-D-21-
F. Pore Fluid Loop Shutdown Procedures
1. Close valves P2 (counterclockwise). P P3. P4. P6. P14. P5.
and P13.V
2. Open valves P7. P. P12. P16. and 17.
3. Crack open valve P15 until the pore pressure in the fluid loop
is reduced to the desired pressure.
-D-22-
& *
Figure 1
FRACTURE FLOW EXPERIMENTAL APPARATUS SCHEMATIC
HOUSE AIR
VACUUM PUMP
D AIR
FLUID. 9tOIR v
AIR ~~~PORE WATER
] + LIUID + X RESERVOIR
UPORE WATERCOLLECTION
ACCUMULATORS
, . @~~~~~~~~~~~~~ REGULATING VALVE
HIGH PRESSURE VESSEL-*-f METERING VALVE
CORE 75PESSREPAUG
VACUUMi< = @ VACUUM GAUGEPLATEN C FILTER
CORE ._ . _ __ s :0 PRESSURE REUEF VALVE
14
Sandia National Laboratoriesdate: January 31, 1984 Albuquerque. New Mexico 87185
to: Ton Cabe, 6255Pressu Safety Advisor
from: B. . Schwartz, 6313
subject: Pressure Safety Analysis for Fracture Flow Apparatus
List of Subiects
1. Introduction2. System Description3. Stored Energy Calculations4. Toxic Materials5. Safety Factors6. Material Behavior7. Schematic of Fracture Flow Apparatus8. Conclusions
Introduction
In accordance with policies and practices set forth by Sandia NationalLaboratories Pressure Advisory Committeee (Pressure safety practices man-ual SAND76-0424, Change 1) the pressure system for fracture flow experi-ments is herein being presented, including an estimate of containedenergy of the system. The purpose of this Pressure Safety Analysis (PSA)is to document that the system has been designed to operate safely andwill not require a Pressure Safety Analysis Report (PSAR).
A signature sheet is provided at the end to indicate that this analysishas been reviewed by the 6313 pressure safety advisor, Safety Engineering(Division 3442) and approved by the 6313 supervisor.
2. System Description
In support of the Nevada Nuclear Waste Storage Investigations (NNWSI)program, flow through fractures in tuff rocks is being investigated. Acore sample approximately 2-2.5 inches in diameter by 2-6 inches inlength will be enclosed in a core holder containing electrical leadsattached to the sample. The core holder is enclosed in a pressure vesselwhich will provide a onfining pressure of less than or equal to 2,500psi to simulate the in situ pressures on the sample. One pump and anaccumulator will maintain the confining pressure.
-D-24-
The fluid passing through the sample will be distilled water or J-13 water(from a well near the drill holes). An electrolyte may be added to enhanceimpedance measurements across the sample. A pore pressure of lest than orequal to 650 psi vill be used to drive water through the sample. A flowmeter upstream from the inlet will monitor the flow rate. The outlet fluidflow will be monitored with a second flow meter. Back pressure may be main-tained with a fine metering valve.
Pressures will be measured at the inlet and outlet ports of the pressurevessel using pressure transducers. This document defines testing to be per-formed at ambient temperatures. However, future testing may incorporateelevated temperatures. Although the equipment defined in this study havebeen designed to operate at elevated temperatures, a revision of this PSAwill be made prior to any high pressure/temperature testing.
3. Stored Energv Calculations
Requirement: The contained energy of a liquid system (ET) must be below4.0 x 104 Joule (Section 3.5.2.1 paragraph dl)
Total stored energy in a single phase liquid system (ET)
ET eL + S'
where
eL Energy stored in the compressed liquid
eS = Strain energy stored in the vessel
Vote: Multiply ft - lbs by 1.356 to et Joules
eL kB
where P = 3000 psi = Maximum Allowable Working Pressure (MAWP)V Volume of Pressure Vessel 236 in3
B = Liquid bulk modulus 225,000k = constant * 24 when P. are in psi units
e . (3000)2 236 394 ft - lb or 535 Joules(24) 225,000
-D-25-
,n 2Yt± (1.25 - u)-k~t
where P 3000 psi - MAWPV * 236 In3
d Inside Diameter of Vessel 5 in.k constant a 24 when P is in psi units3 a Younss Modulus 28 5 x 106 psi 't * Wall thickness of essel 1 in.u * Poisson Ratio 0.3 (*)
C') For Vessel Material 17-4PH Stainless Steel Aged at 900'F
as (30002) (236) C5) (1.25 - 0.3) 14.8 - lb or 20.0 Joules
(24) 28.5x106 (1)
ET 535 Joules + 20 JoulesIT a 5.55 x 102 Joules
Therefore, our calculated total stored energy of 5.55 x 102 Joules is lessthan the value of 4.0 x 14 Joules at which a Pressure Safety AnalysisReport is required.
4. Toxic Materials
Requirement: No toxic or flammable materials are involved (Section3.5.2.1 paragraph d2)
The confining fluid will be silicone based. Silicone fluids areessentially nontoxic and nonflamable. The silicone fluid used willhave a flash point of greater than or equal to 450'? (2326C). The seal-ant used in the core holder will be silicone or fluorosilicone based.They are both essentially nontoxic and nonflammable. Both sealants havea flash point greater than 392F (200C).
5. Safety Factors
Requirements: o credible potential for serious injury or unacceptableproperty damage (Section 3.5.2.1. paragraph d.3)
Table I documents the safety margins designed into each component of thesystem. Section 3.24 recommends that the hihest operating pressure beless than or equal to 85 percent of the HAWP.
*Dow Corning 200 fluid (200cs).
-D-26-
TABLE 1Safety Factors of Equipment.
Ia
Component Manufacturer Operating MAWP Proof Test Predicted RupturePressure 025-C 0 25-C e 25-C @ 25 C
(PSI) (PSI) (PSI) (PSI)
Pressure Vessel S-Bell 2500 3000 10,000 >15,000
Flow meters Flow 650 750 (1) 15,000MeasurementSystems
Pressure Precise 650 750 1,200 3,000Transducer Sensors 2500 3000 5.000 >12,000
Air Driven Hnskel 650 750 (1) 9,000Liquid Pumps 2500 3000 (2) 12,000
Accumulators Hydrodyne 650 750 4,500 12,0002500 3000 4,500 12,000
316 Stainless 0.125 I.D. 2500 3000 - Safety FnetorSteel 1/4" OD 0.180 I.D. 650 750 - of 8Tubing
Valves 2500 3000 - Safety Factorof 8
316 Stainless 2500 3000 - Safety FactorSteel Fittings of 8
*Maxifum allowable working pressure(1) will proof test at SNLA to 1,200 PSI(2) Will proof test at SLA to 4,500 PSI
6. Material Behavior
Requirement: Material Behavior is predictably nonbrittle.
Jon unford of Physical Metallurgy (Division 1832) has evaluated the materialand heat treatment used in fabricating the pressure vessel. In a memo to -Schwartz dated 3/2/84, unford approved the pressure vessel for its intendeduse as described in this analysis.
The following recommendations made by Munford will be addressed in the SafeOperating Procedure (SOP) which shall be written simultaneously with theassembly of this experimental apparatus.
1) The LAWP shall be less than or equal to 3000 PSI.
2) The maximum temperature shall be less than or equal to 200C.
The minimum temperature shall be reater than or equal to the ambientlaboratory conditions and no means shall be used to lower the vesseltemperature below ambient temperature conditions.
3) The total number of pressure cycles on the vessel shall not exceed500 at which time the vessel shall be discarded.
4) The vessel shall not be "shock loaded" i.e., pressure cycling fromambient to the AWP and/or cycling from the MAWP to ambient pressureshould take at least ten seconds.
5) The pressure vessel shall not be exposed to corrosive environments.
7. Schematic of Fracture Flow Apparatus
(See Figure 1)
8. Conclusions
The calculated total stored energy of the fracture flow apparatus is 555 x102 Joules. This stored energy is less than the value of 4.0 x 104 Joulesat which a PSAR is required. This analysis has also addressed the design ofthe system as concerns toxic materials, safety factors, and material behavior.A schematic of the apparatus has also been included. Consideration of the lowstored energy. the lack of toxic materials, the presence of adequate safetyfactors and limitations related to material behavior lead to the conclusion -that a PSAR is not required according to the Sandia Pressure Safety Manual,SAND76-0424, Change 1.
-D-28-
r 4 4r
Pigure I
FRACTURE FLOW EXPERIMENTAL APPARATUS SCHEMATIC
HOUSE AIR
COMPRESSED AIR
CONFINING FLUID
Ia1�31
PORE WATERCOLLECTION
@ FLOW METER0 REGULATING VALVE@ METERING VALVED CHECK VALVE
0 PRESSURE GAUGEo VACUUM GAUGE
CM FILTER0 PRESSURE RELIEF VALVE
izL0
Div. 6313 Hih Pressure Fracture Flow ExperimentalApparatus Signature Sheet
Reviewed by
Reviewed by
Reviewed by
Approved by
Tom Cabe, 6255Pressure Safety Advisor
Don Joe \,,42Safety Consultant
D. Rost, 3442Division Supervisor
DiiTi onrson, 633D vision Spervisor
De-21-Date
Date
.3A to / YDate'
-I
-D-30-
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Engineering GeologyU.S. Geological Survey106 National Center12201 Sunrise Valley Dr.Reston, VA 22092
V. M. GlanzmanU.S. Geological SurveyP.O. Box 25046913 Federal CenterDenver, CO 80225
C. H. JohnsonTechnical Program ManagerNuclear Waste Project OfficeState of NevadaEvergreen Center, Suite 2521802 North Carson StreetCarson City, NV 89710
John FordhamDesert Research InstituteWater Resources CenterP.O. Box 60220Reno, NV 89506
Prof. S. W. DicksonDepartment of Geological SciencesMackay School of MinesUniversity of NevadaReno, NV 89557
J. R. RolloDeputy Assistant Director for
Engineering GeologyU.S. Geological Survey106 National Center12201 Sunrise Valley Dr.Reston, VA 22092
Eric AndersonMountain West Research-Southwest
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Judy Foremaster (5)City of CalienteP.O. Box 158Caliente. NV 89008
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T. Hay, Executive AssistantOffice of the GovernorState of NevadaCapitol ComplexCarson City, NV 89710
R. R. Loux, Jr., (3)Executive DirectorNuclear Waste Project OfficeState of NevadaEvergreen Center, Suite 2521802 North Carson StreetCarson City, NV 89710
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Geotechnical EngineeringUniversity of ArizonaTucson, AZ 85721
Department of Comprehensive PlanningClark County225 Bridger Avenue, 7th FloorLas Vegas, NV 89155
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Planning DepartmentNye CountyP.O. Box 153Tonopah, NV 89049
Director of Community PlanningCity of Boulder CityP.O. Box 367Boulder City, NV 89005
Commission of the EuropeanCommunities
200 Rue de la LoiB-1049 BrusselsBelgium
Lincoln County CommissionLincoln CountyP.O. Box 90Pioche, V 89043
Community Planning & DevelopmentCity of North Las VegasP.O. Box 4086North Las Vegas, NV 89030
City ManagerCity of HendersonHenderson, NV 89015
ONWI LibraryBattelle Columbus LaboratoryOffice of Nuclear Waste Isolation505 King AvenueColumbus, OH 43201
LibrarianLos Alamos Technical
Associates, Inc.P.O. Box 410Los Alamos, NM 87544
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